Item 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

Ameren, headquartered in St. Louis, Missouri, is a public utility holding company under PUHCA 2005. Ameren’s primary assets are its equity interests in its subsidiaries, including Ameren Missouri and Ameren Illinois. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. Dividends on Ameren’s common stock and the payment of expenses by Ameren depend on distributions made to it by its subsidiaries.

Below is a summary description of Ameren Missouri and Ameren Illinois. A more detailed description can be found in Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report.

•	Ameren Missouri operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas transmission and distribution business in Missouri.

•	Ameren Illinois operates rate-regulated electric and natural gas transmission and distribution businesses in Illinois.

Ameren has various other subsidiaries that conduct activities such as the provision of shared services. Ameren also has a subsidiary, ATXI, that operates a FERC rate-regulated electric transmission business. ATXI is developing MISO-approved electric transmission projects, including the Illinois Rivers, Spoon River, and Mark Twain projects. Ameren is also pursuing projects to improve electric transmission system reliability within Ameren Missouri's and Ameren Illinois' service territories as well as competitive electric transmission investment opportunities outside of these territories, including investments outside of MISO.

Unless otherwise stated, the following sections of Management's Discussion and Analysis of Financial Condition and Results of Operations exclude discontinued operations for all periods presented. See Note 16 – Divestiture Transactions and Discontinued Operations under Part II, Item 8, of this report for additional information regarding that presentation.

Ameren's financial statements are prepared on a consolidated basis, and therefore include the accounts of its majority-owned subsidiaries. Ameren Missouri and Ameren Illinois have no subsidiaries, and therefore their financial statements are not prepared on a consolidated basis. All intercompany transactions have been eliminated. All tabular dollar amounts are in millions, unless otherwise indicated.

In addition to presenting results of operations and earnings amounts in total, we present certain information in cents per share. These amounts reflect factors that directly affect Ameren’s earnings. We believe this per share information helps readers to understand the impact of these factors on Ameren’s earnings per share. All references in this report to earnings per share are based on average diluted common shares outstanding.

OVERVIEW

Ameren’s strategic plan includes investing in and operating its utilities in a manner consistent with existing regulatory frameworks, enhancing those frameworks and advocating for responsible energy policies, as well as creating and capitalizing on opportunities for investment for the benefit of its customers and shareholders. In 2015, Ameren continued to successfully execute its strategy to invest in and to grow its utilities through investment in rate-regulated infrastructure while remaining focused on operational improvement and disciplined cost management. Ameren continues to allocate significant amounts of capital to those businesses that are supported by constructive regulatory frameworks, investing $1.3 billion in its FERC-regulated electric transmission and Illinois electric and natural gas delivery businesses. Reflecting confidence in Ameren’s long-term strategy and outlook, Ameren’s board of directors increased the quarterly dividend rate in October 2015.

With respect to the FERC-regulated electric transmission businesses, there are currently two complaint cases filed with the FERC seeking a reduction in the allowed base return on common equity under the MISO tariff. In December 2015, an administrative law judge issued an initial decision in the November 2013 complaint case that would lower the allowed base return on common equity to 10.32%. The FERC is expected to issue a final order on the November 2013 complaint case by October 2016. An initial decision from an administrative law judge in the February 2015 complaint case, which will subsequently require FERC approval, is expected to be issued by June 30, 2016. In January 2015, a FERC-approved incentive adder of up to 50 basis points on the allowed base return on common equity for our participation in an RTO became effective. Beginning with its January 2015 effective date, the incentive adder will reduce any refund to customers relating to a reduction of the allowed base return on common equity from the complaint cases.

In December 2015, the ICC issued an order in Ameren Illinois’ annual update filing approving a $106 million increase in Ameren Illinois’ electric delivery service revenue requirement beginning in January 2016. Additionally, in December 2015, the ICC issued a rate order that approved an increase in revenues for Ameren Illinois' natural gas delivery service of $45 million. The rate order also approved the VBA for residential and small nonresidential customers beginning in 2016.

Ameren is evaluating the Clean Power Plan's potential impacts to its operations, including those related to electric system reliability, and its level of investment in customer energy efficiency programs, renewable energy, and other forms of generation investment. In February 2016, the United States Supreme Court stayed the Clean Power Plan and all implementation requirements until such time as legal appeals are concluded. The District of Columbia Circuit Court of Appeals has scheduled hearings for June 2016 on the legality of the rule. A decision by the District of Columbia Circuit Court of Appeals is expected to be issued later this year and additional appeals before the United States Supreme Court are likely. Appeals are

not expected to conclude prior to 2018. Ameren will continue to advocate for responsible energy policies related to the Clean Power Plan while working with key stakeholders to address important issues associated with the Missouri and Illinois state implementation plans should the Clean Power Plan ultimately be upheld.

Ameren Missouri continues to seek legislative solutions to address regulatory lag and to support investment in its utility infrastructure for the benefit of its customers, including through its advocacy for a legislative solution to support Noranda's operations. On January 8, 2016, Ameren Missouri’s largest customer, Noranda, announced that production had been idled at two of its three pot lines at the smelter following an electric supply circuit failure on assets not owned by Ameren Missouri. On February 8, 2016, Noranda filed voluntary petitions for a court-supervised restructuring process under Chapter 11 of the United States Bankruptcy Code. In the filing, Noranda reaffirmed that the remaining pot line will continue to operate at the smelter until March 2016, at which time operation of the line will be curtailed. Noranda stated it would maintain the flexibility to restart operations at the smelter should conditions allow. In January 2016, Ameren Missouri filed a notice with the MoPSC that would enable Ameren Missouri to file an electric rate case after 60 days. Ameren Missouri expects to file an electric rate case in 2016 and expects the resulting new rates to reflect Noranda’s actual sales volumes which would prospectively eliminate the impact of the current revenue shortfall. Ameren Missouri may seek recovery of lost revenues in a filing with the MoPSC for certain costs incurred but not contemporaneously recovered as a result of Noranda’s reduced operations. Ameren Missouri will continue to monitor Noranda’s sales volumes and to evaluate its regulatory and legislative options that might mitigate adverse financial impacts.

In February 2016, the MoPSC issued an order approving Ameren Missouri’s March 2016 to February 2019 MEEIA plan which included a portfolio of customer energy efficiency programs along with a rider to collect the program costs, the throughput disincentive, and a performance incentive from customers. The plan provides Ameren Missouri an opportunity to earn additional revenues by achieving certain customer energy efficiency goals, including $27 million if 100% of the goals are achieved during the three-year period, with the potential to earn more if Ameren Missouri's energy savings exceed those goals.

Earnings

Net income attributable to Ameren common shareholders from continuing operations was $579 million, or $2.38 per diluted share, for 2015, and $587 million, or $2.40 per diluted share, for 2014. These earnings were unfavorably affected in 2015, compared with 2014, by a provision recognized as a result of Ameren Missouri’s discontinued efforts to license and build a second nuclear unit at its existing Callaway energy center site as well as decreased electric and natural gas sales volumes primarily due to warmer winter temperatures. Additionally, increased net financing costs at Ameren Missouri and increased depreciation and amortization expenses for those businesses not operating under formula rates unfavorably affected earnings. The absence in 2015 of a recovery of certain previously disallowed

debt premium costs per the ICC's December 2014 order also negatively affected earnings. The decrease in Ameren's net income from continuing operations was partially offset by increased Ameren Illinois and ATXI electric transmission service and Ameren Illinois electric delivery service earnings, reflecting Ameren’s strategy to allocate significant capital to those businesses. Earnings were positively affected by the absence of a Callaway energy center scheduled refueling and maintenance outage at Ameren Missouri as well as increased Ameren Illinois earnings resulting from a January 2015 ICC order regarding Ameren Illinois’ cumulative power usage cost and its purchased power rider mechanism. Decreased operations and maintenance expenses primarily at Ameren Missouri and at nonregistrant subsidiaries and decreased interest expense at Ameren (parent) also favorably affected earnings.

Liquidity

Cash generated by operating activities associated with continuing operations and by issuances of long-term debt were used to fund capital expenditures, repay short-term debt, and pay dividends to common shareholders. At December 31, 2015, Ameren, on a consolidated basis, had available liquidity, in the form of cash on hand and amounts available under existing credit agreements, of $2.1 billion.

Capital Spending

In 2015, Ameren made significant investments in its utilities. It expects that trend to continue into the future. From 2016 through 2020, Ameren's cumulative capital spending is projected to range between $10.6 billion and $11.5 billion. The projected spending includes $4.1 billion, $6.0 billion, and $1.0 billion for Ameren Missouri, Ameren Illinois, and ATXI, respectively. In December 2015, a federal tax law was enacted that authorized the continued use of bonus deprecation that allows for an acceleration of deductions for tax purposes. Bonus depreciation is expected to increase cash flow through at least 2020. Ameren expects to use this incremental cash flow to make investments in utility infrastructure for the benefit of its customers.

RESULTS OF OPERATIONS

Our results of operations and financial position are affected by many factors. Weather, economic conditions, energy efficiency investments by our customers and us, and the actions of key customers can significantly affect the demand for our services. Our results are also affected by seasonal fluctuations in winter heating and summer cooling demands. We are also affected by nuclear refueling and other energy center maintenance outages at Ameren Missouri. Additionally, fluctuations in interest rates and conditions in the capital and credit markets affect our cost of borrowing and our pension and postretirement benefits costs. Almost all of Ameren’s revenues are subject to state or federal regulation. This regulation has a material impact on the prices we charge for our services. Our results of operations, financial position, and liquidity are affected by our ability to align our overall spending, both operating and capital, with regulatory frameworks established by our regulators.

Ameren Missouri principally uses coal, nuclear fuel, and natural gas for fuel in its electric operations and purchases natural gas for its customers. Ameren Illinois purchases power and natural gas for its customers. The prices for these commodities can fluctuate significantly because of the global economic and political environment, weather, supply and demand, and many other factors. We have natural gas cost recovery mechanisms for our Illinois and Missouri natural gas delivery service businesses, a purchased power cost recovery mechanism for Ameren Illinois' electric delivery service business, and a FAC for Ameren Missouri's electric utility business.

Ameren Illinois' electric delivery service utility business, pursuant to the IEIMA, conducts an annual reconciliation of the revenue requirement necessary to reflect the actual costs incurred in a given year with the revenue requirement included in customer rates for that year, with recoveries from, or refunds to, customers made in a subsequent year. Included in Ameren Illinois' revenue requirement reconciliation is a formula for the return on equity, which is equal to the average of the monthly yields of 30-year United States Treasury bonds plus 580 basis points. Therefore, Ameren Illinois' annual return on equity is directly correlated to yields on United States Treasury bonds. Ameren Illinois and ATXI use a company-specific, forward-looking rate formula framework in setting their transmission rates. These forward-looking rates are updated each January with forecasted information. A reconciliation during the year, which adjusts for the actual revenue requirement and actual sales volumes, is used to adjust billing rates in a subsequent year.

Ameren Illinois’ and ATXI’s electric transmission service businesses and Ameren Illinois’ electric delivery service business operate under formula ratemaking, designed to provide for the recovery of actual costs of service that are prudently incurred as well as a return on equity. While rate-regulated, Ameren Illinois’ natural gas business and Ameren Missouri do not operate under formula ratemaking. Ameren (parent) is not rate-regulated.

We employ various risk management strategies to reduce our exposure to commodity risk and other risks inherent in our business. The reliability of Ameren Missouri's energy centers and our transmission and distribution systems and the level of purchased power costs, operations and maintenance costs, and capital investment are key factors that we seek to manage in order to optimize our results of operations, financial position, and liquidity.

Earnings Summary

The following table presents a summary of Ameren's earnings for the years ended December 31, 2015, 2014, and 2013:

	2015				2014				2013
Net income attributable to Ameren common shareholders	$	630			$	586			$	289
Earnings per common share – diluted	2.59				2.40				1.18
Net income attributable to Ameren common shareholders – continuing operations	579				587				512
Earnings per common share – diluted – continuing operations	2.38				2.40				2.10

2015 versus 2014

Net income attributable to Ameren common shareholders from continuing operations in 2015 decreased $8 million, or $0.02 per diluted share, from 2014. The decrease was due to a $38 million decrease in net income from the Ameren Missouri segment, partially offset by a $13 million increase in net income from the Ameren Illinois segment. Net income from nonregistrant subsidiaries and Ameren (parent) in 2015 was $13 million compared with a $4 million net loss in 2014, which included net income from ATXI of $31 million and $13 million, respectively.

In 2015, net income attributable to Ameren common shareholders from discontinued operations was favorably affected by the recognition of a tax benefit resulting from the removal of a reserve for unrecognized tax benefits of $53 million recorded in 2013 related to the divestiture of New AER, based on the completion of the IRS audit of Ameren’s 2013 tax year.

Compared with 2014, 2015 earnings per share from continuing operations were unfavorably affected by:

•	a provision recognized in the second quarter of 2015 as a result of Ameren Missouri’s discontinued efforts to license and build a second nuclear unit at its existing Callaway energy center site (18 cents per share);

•	decreased electric and natural gas sales volumes primarily due to warmer winter temperatures in 2015 (estimated at 6 cents per share);

•	increased net financing costs at Ameren Missouri, primarily due to a reduction in allowance for funds used during construction as multiple significant electric capital projects were completed in 2014 (6 cents per share);

•	increased depreciation and amortization expenses for those businesses not operating under formula rates, primarily resulting from electric capital additions completed in 2014 at Ameren Missouri, which were not reflected in customer rates until May 30, 2015, and amortization of natural gas-related investments at Ameren Illinois (5 cents per share); and

•	the absence in 2015 of a recovery of certain previously disallowed debt premium costs per the ICC's December 2014 order (3 cents per share).

Compared with 2014, 2015 earnings per share from continuing operations were favorably affected by:

•	increased Ameren Illinois and ATXI electric transmission service and Ameren Illinois electric delivery service earnings under formula ratemaking, primarily due to additional rate

base investment as well as interest earned on the revenue requirement reconciliation adjustment regulatory assets (20 cents per share). These earnings were reduced by the recognition of a liability for a potential refund to customers based on the pending FERC complaint cases regarding the allowed base return on common equity as well as a lower return on equity related to Ameren Illinois electric delivery service investments due to a reduction in the 30-year United States Treasury bond yields (5 cents per share);

•	the absence of a Callaway energy center scheduled refueling and maintenance outage in 2015, which last occurred in the fourth quarter of 2014, partially offset by preparation costs incurred in 2015 for the 2016 scheduled refueling outage (7 cents per share);

•	increased Ameren Illinois earnings resulting from a January 2015 ICC order regarding Ameren Illinois’ cumulative power usage cost and its purchased power rider mechanism (4 cents per share);

•	excluding the scheduled refueling and maintenance outage, MEEIA program costs, and expenses with corresponding increases in electric revenues resulting from the April 2015 MoPSC electric rate order, decreased other operations and maintenance expenses at Ameren Missouri primarily because of decreased energy center costs and at nonregistrant subsidiaries (4 cents per share); and

•	decreased interest expense at Ameren (parent), primarily due to the maturity of higher-cost debt in 2014 being replaced with lower-cost debt (3 cents per share).

The cents per share information presented above is based on the diluted average shares outstanding in 2014.

2014 versus 2013

Net income attributable to Ameren common shareholders from continuing operations in 2014 increased $75 million, or $0.30 per diluted share, from 2013. The increase was due to a $41 million increase in net income from the Ameren Illinois segment and a $39 million decrease in net loss from Ameren (parent) and nonregistrant subsidiaries, which included an increase in ATXI's net income of $6 million. The increase was partially offset by a $5 million decrease in net income from the Ameren Missouri segment.

Compared with 2013, 2014 earnings per share from continuing operations were favorably affected by:

•	higher natural gas rates at Ameren Illinois pursuant to a December 2013 order (8 cents per share);

•	decreased interest expense, excluding the effects of the ICC's December 2014 order discussed below, primarily due to the maturity of higher-cost debt replaced with issuances of lower-cost debt (8 cents per share);

•	the absence in 2014 of a reduction in Ameren Missouri

revenues resulting from a July 2013 MoPSC order that required a refund to customers associated with certain long-term partial requirements sales recognized from October 1, 2009, to May 31, 2011 (7 cents per share);

•	the ICC's December 2014 order allowing partial recovery of certain previously disallowed debt premium costs that were charged to earnings in 2013 (7 cents per share);

•	an increase in Ameren Illinois' and ATXI's electric transmission earnings under formula ratemaking due to additional rate base investment, partially offset by the recognition of a liability for a potential refund to customers based on the pending FERC November 2013 complaint case regarding the allowed base return on common equity (6 cents per share);

•	an increase in Ameren Illinois’ electric delivery service earnings under formula ratemaking pursuant to the IEIMA due to increased rate base investment (estimated at 5 cents per share);

•	increased net shared benefits realized under the MEEIA at Ameren Missouri (4 cents per share), which were partially offset by lower revenues resulting from reduced demand due to customer energy efficiency programs; and

•	increased electric and natural gas sales volumes primarily resulting from colder winter temperatures in early 2014 and warmer early summer temperatures (estimated at 1 cent per share).

Compared with 2013, 2014 earnings per share from continuing operations were unfavorably affected by:

•	increased depreciation and amortization expenses, primarily resulting from electric distribution capital additions at Ameren Missouri (5 cents per share);

•	an increase in the effective tax rate (4 cents per share); and

•	increased other operations and maintenance expenses for Ameren Missouri and for Ameren Illinois' natural gas business, primarily due to increased labor and litigation costs, offset in part by decreased costs at Ameren (parent), primarily resulting from the substantial elimination of costs previously incurred in support of the divested merchant generation business (3 cents per share).

The cents per share information presented above is based on the diluted average shares outstanding in 2013.

For additional details regarding the Ameren Companies’ results of operations, including explanations of Margins, Other Operations and Maintenance Expenses, Provision for Callaway Construction and Operating License, Depreciation and Amortization, Taxes Other Than Income Taxes, Other Income and Expenses, Interest Charges, Income Taxes, and Income (Loss) from Discontinued Operations, Net of Taxes, see the major headings below.

Below is a table of income statement components by segment for the years ended December 31, 2015, 2014, and 2013:

2015	Ameren Missouri				Ameren Illinois				Other / Intersegment Eliminations				Total
Electric margins	$	2,481			$	1,263			$	44			$	3,788
Natural gas margins	80				425				(2		)		503
Other revenues	2				—				(2		)		—
Other operations and maintenance	(925		)		(797		)		28				(1,694		)
Provision for Callaway construction and operating license	(69		)		—				—				(69		)
Depreciation and amortization	(492		)		(295		)		(9		)		(796		)
Taxes other than income taxes	(335		)		(130		)		(8		)		(473		)
Other income and (expenses)	41				9				(6		)		44
Interest charges	(219		)		(131		)		(5		)		(355		)
Income taxes	(209		)		(127		)		(27		)		(363		)
Income from continuing operations	355				217				13				585
Income from discontinued operations, net of taxes	—				—				51				51
Net income	355				217				64				636
Noncontrolling interests – preferred dividends	(3		)		(3		)		—				(6		)
Net income attributable to Ameren common shareholders	$	352			$	214			$	64			$	630
2014
Electric margins	$	2,436			$	1,179			$	11			$	3,626
Natural gas margins	82				443				—				525
Other revenues	1				—				(1		)		—
Other operations and maintenance	(939		)		(771		)		26				(1,684		)
Depreciation and amortization	(473		)		(263		)		(9		)		(745		)
Taxes other than income taxes	(322		)		(138		)		(8		)		(468		)
Other income	48				9				—				57
Interest charges	(211		)		(112		)		(18		)		(341		)
Income taxes	(229		)		(143		)		(5		)		(377		)
Income (loss) from continuing operations	393				204				(4		)		593
Loss from discontinued operations, net of taxes	—				—				(1		)		(1		)
Net income (loss)	393				204				(5		)		592
Noncontrolling interests – preferred dividends	(3		)		(3		)		—				(6		)
Net income (loss) attributable to Ameren common shareholders	$	390			$	201			$	(5	)		$	586
2013
Electric margins	$	2,401			$	1,081			$	(3	)		$	3,479
Natural gas margins	83				399				(2		)		480
Other revenues	1				3				(4		)		—
Other operations and maintenance	(909		)		(693		)		(9		)		(1,611		)
Depreciation and amortization	(454		)		(243		)		(9		)		(706		)
Taxes other than income taxes	(319		)		(132		)		(7		)		(458		)
Other income and (expenses)	47				1				(5		)		43
Interest charges	(210		)		(143		)		(45		)		(398		)
Income (taxes) benefit	(242		)		(110		)		41				(311		)
Income (loss) from continuing operations	398				163				(43		)		518
Loss from discontinued operations, net of taxes	—				—				(223		)		(223		)
Net income (loss)	398				163				(266		)		295
Noncontrolling interests – preferred dividends	(3		)		(3		)		—				(6		)
Net income (loss) attributable to Ameren common shareholders	$	395			$	160			$	(266	)		$	289

Margins

The following table presents the favorable (unfavorable) variations by segment for electric and natural gas margins in 2015 compared with 2014, as well as 2014 compared with 2013. Electric margins are defined as electric revenues less fuel and purchased power costs. Natural gas margins are defined as gas revenues less gas purchased for resale. We consider electric and natural gas margins useful measures to analyze the change in profitability of our electric and natural gas operations between periods. We have included the analysis below as a complement to the financial information we provide in accordance with GAAP. However, these margins may not be a presentation defined under GAAP, and they may not be comparable to other companies’ presentations or more useful than the GAAP information we provide elsewhere in this report.

2015 versus 2014	Ameren Missouri				Ameren Illinois				Other(a)				Ameren
Electric revenue change:
Effect of weather (estimate)(b)	$	(20	)		$	(10	)		$	—			$	(30	)
Base rates (estimate)	82				34				—				116
Sales volume (excluding the estimated effect of weather)	(36		)		(1		)		—				(37		)
Off-system sales and transmission services revenues	3				—				—				3
MEEIA net shared benefits	33				—				—				33
Transmission services revenues(c)	1				29				37				67
Purchased power rider order	—				15				—				15
Other	2				(7		)		(13		)		(18		)
Cost recovery mechanisms – offset in fuel and purchased power(d)
Power supply costs	—				81				—				81
Transmission services recovery mechanism	—				10				—				10
Recovery of FAC under-recovery	(5		)		—				—				(5		)
Other cost recovery mechanisms(e)
Bad debt, energy efficiency programs, and environmental remediation cost riders	—				10				—				10
Gross receipts tax	6				—				—				6
MEEIA program costs	16				—				—				16
Total electric revenue change	$	82			$	161			$	24			$	267
Fuel and purchased power change:
Energy costs	$	21			$	—			$	—			$	21
Effect of weather (estimate)(b)	10				10				—				20
Effect of higher net energy costs included in base rates	(65		)		—				—				(65		)
FAC exclusion of transmission services expenses(c)	(7		)		—				—				(7		)
Other	(1		)		4				9				12
Cost recovery mechanisms – offset in electric revenue(d)
Power supply costs	—				(81		)		—				(81		)
Transmission services recovery mechanism	—				(10		)		—				(10		)
Recovery of FAC under-recovery	5				—				—				5
Total fuel and purchased power change	$	(37	)		$	(77	)		$	9			$	(105	)
Net change in electric margins	$	45			$	84			$	33			$	162
Natural gas revenue change:
Effect of weather (estimate)(b)	$	(17	)		$	(72	)		$	—			$	(89	)
Other	2				1				(2		)		1
Cost recovery mechanism – offset in gas purchased for resale(d)
Purchased gas costs	(11		)		(113		)		—				(124		)
Other cost recovery mechanisms(e)
Bad debt, energy efficiency programs, and environmental remediation cost riders	—				(2		)		—				(2		)
Gross receipts tax	(1		)		(7		)		—				(8		)
Total natural gas revenue change	$	(27	)		$	(193	)		$	(2	)		$	(222	)
Gas purchased for resale change:
Effect of weather (estimate)(b)	$	14			$	62			$	—			$	76
Cost recovery mechanism – offset in natural gas revenue(d)
Purchased gas costs	11				113				—				124
Total gas purchased for resale change	$	25			$	175			$	—			$	200
Net change in natural gas margins	$	(2	)		$	(18	)		$	(2	)		$	(22	)

2014 versus 2013	Ameren Missouri				Ameren Illinois				Other(a)				Ameren
Electric revenue change:
Effect of weather (estimate)(b)	$	8			$	(5	)		$	—			$	3
Base rates (estimate)	—				56				—				56
Sales volume (excluding the estimated effect of weather)	(22		)		3				—				(19		)
Off-system sales and transmission services revenues	(12		)		—				—				(12		)
FAC prudence review order in 2013	25				—				—				25
MEEIA net shared benefits	15				—				—				15
Transmission services revenues	—				10				14				24
Other	2				6				(3		)		5
Cost recovery mechanisms – offset in fuel and purchased power(d)
Power supply costs	—				(38		)		—				(38		)
Transmission services recovery mechanism	—				4				—				4
Recovery of FAC under-recovery	(14		)		—				—				(14		)
Other cost recovery mechanisms(e)
Bad debt, energy efficiency programs, and environmental remediation cost riders	—				25				—				25
MEEIA program costs	7				—				—				7
Total electric revenue change	$	9			$	61			$	11			$	81
Fuel and purchased power change:
Energy costs	$	18			$	—			$	—			$	18
Effect of weather (estimate)(b)	(5		)		—				—				(5		)
Other	(1		)		3				3				5
Cost recovery mechanisms – offset in electric revenue(d)
Power supply costs	—				38				—				38
Transmission services recovery mechanism	—				(4		)		—				(4		)
Recovery of FAC under-recovery	14				—				—				14
Total fuel and purchased power change	$	26			$	37			$	3			$	66
Net change in electric margins	$	35			$	98			$	14			$	147
Natural gas revenue change:
Effect of weather (estimate)(b)	$	6			$	32			$	—			$	38
Base rates (estimate)	—				32				—				32
Other	(2		)		1				2				1
Cost recovery mechanism – offset in gas purchased for resale(d)
Purchased gas costs	(1		)		57				—				56
Other cost recovery mechanisms(e)
Bad debt, energy efficiency programs, and environmental remediation cost riders	—				4				—				4
Gross receipts tax	—				3				—				3
Total natural gas revenue change	$	3			$	129			$	2			$	134
Gas purchased for resale change:
Effect of weather (estimate)(b)	$	(5	)		$	(28	)		$	—			$	(33	)
Cost recovery mechanism – offset in natural gas revenue(d)
Purchased gas costs	1				(57		)		—				(56		)
Total gas purchased for resale change	$	(4	)		$	(85	)		$	—			$	(89	)
Net change in natural gas margins	$	(1	)		$	44			$	2			$	45

(a)	Primarily includes amounts for ATXI and intercompany eliminations.

(b)	Represents the estimated variation resulting primarily from changes in cooling and heating degree-days on electric and natural gas demand compared with the prior year; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(c)	Ameren Missouri amounts are subsequent to May 30, 2015, due to the exclusion of transmission revenues and substantially all transmission charges from the FAC as a result of the April 2015 MoPSC electric rate order.

(d)	Electric and natural gas revenue changes are offset by corresponding changes in Fuel, Purchased power, and Gas purchased for resale, resulting in no change to electric and gas margins.

(e)	See Other Operations and Maintenance Expenses or Taxes Other Than Income Taxes in this section for the related offsetting increase or decrease to expense. These items have no overall impact on earnings.

2015 versus 2014

Ameren Corporation

Ameren's electric margins increased $162 million, or 4%, in 2015 compared with 2014. Ameren's natural gas margins decreased $22 million, or 4%, in 2015 compared with 2014. These results were primarily driven by Ameren Missouri and Ameren Illinois results, as discussed below. Ameren's electric margins also reflect the results of operations of ATXI. ATXI’s transmission services revenues increased $37 million in 2015 compared with 2014 because of higher rate base investment and recoverable costs under forward-looking formula ratemaking reduced by the recognition of a potential refund to customers based on the pending FERC complaint cases regarding the allowed base return on common equity. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for information regarding the FERC complaint cases.

Ameren Missouri

Ameren Missouri has a FAC cost recovery mechanism that allows it to recover or to refund, through customer rates, 95% of changes in net energy costs greater or less than the amount set in base rates without a traditional rate proceeding, subject to MoPSC prudence reviews.

Net energy costs, as defined in the FAC, include fuel and purchased power costs, including transportation, net of off-system sales. As of May 30, 2015, transmission revenues and substantially all transmission charges are excluded from net energy costs as a result of the April 2015 MoPSC electric rate order, which unfavorably affected margins as discussed below. Ameren Missouri accrues as a regulatory asset net energy costs that exceed the amount set in base rates (FAC under-recovery). Net recovery of these costs through customer rates does not affect Ameren Missouri's electric margins, as any change in revenue is offset by a corresponding change in fuel expense to reduce the previously recognized FAC regulatory asset.

Ameren Missouri's electric margins increased $45 million, or 2%, in 2015 compared with 2014. The following items had a favorable effect on Ameren Missouri's electric margins:

•	Higher MEEIA net shared benefits caused by increased customer implementation of longer-lived energy efficiency offerings and increased non-residential customer participation, which increased revenues by $33 million. Net shared benefits compensated Ameren Missouri for lower sales volumes from energy-efficiency-related volume reductions in current and future periods.

•	Higher electric base rates, effective May 30, 2015, as a result of the April 2015 MoPSC electric rate order, which increased margins by an estimated $17 million. The change in electric base rates is the sum of the change in base rates (estimate) (+$82 million) and the change in effect of higher net energy costs included in base rates (-$65 million) in the table above.

The following items had an unfavorable effect on Ameren

Missouri's electric margins in 2015 compared with 2014:

•

Lower sales volumes primarily caused by the MEEIA programs and other customer energy efficiency measures, and a reduction in Noranda sales volumes. Excluding the estimated effect of weather and reduced sales to Noranda, total retail sales volumes decreased by 1%, which decreased revenues by $25 million. A reduction in Noranda sales volumes decreased revenues by $11 million. Noranda's sales volumes were lower than those reflected in rates established in the April 2015 MoPSC electric rate order. Lower sales volumes led to a decrease in net energy costs of $24 million. The change in net energy costs is the sum of the change in off-system sales and transmission services revenues (+$3 million) and the change in energy costs (+$21 million) in the table above.

•	Winter temperatures in 2015 were warmer compared with 2014, as heating degree-days decreased 19%. The effect of weather decreased margins by an estimated $10 million. The change in margins due to weather is the sum of the effect of weather (estimate) on electric revenues (-$20 million) and the effect of weather (estimate) on fuel and purchased power (+$10 million) in the table above.

•	The exclusion of transmission revenues and substantially all transmission charges from the FAC beginning May 30, 2015, which decreased margins by $6 million. The change in margins as a result of the changes to the FAC is the sum of FAC exclusion of transmission services expenses (-$7 million) and transmission services revenues (+$1 million) in the table above.

Ameren Missouri's natural gas margins were comparable between the years. Ameren Missouri has a cost recovery mechanism for natural gas purchased on behalf of its customers. These pass-through purchased gas costs do not affect Ameren Missouri's natural gas margins as any change in costs is offset by a corresponding change in revenues.

Ameren Illinois

Ameren Illinois' electric revenues increased $161 million in 2015 compared with 2014 primarily due to higher power supply costs as a result of increased MISO capacity prices. Ameren Illinois has a cost recovery mechanism for power purchased and transmission services incurred on behalf of its electric customers. These pass-through costs do not affect Ameren Illinois' electric margins, as any change in costs is offset by a corresponding change in revenues.

The provisions of the IEIMA and the FERC's electric transmission formula rate framework provide for annual reconciliations of the electric delivery and electric transmission service revenue requirements necessary to reflect the actual costs incurred in a given year with the revenue requirements in customer rates for that year, including an allowed return on equity. See Operations and Maintenance Expenses in this section for additional information regarding the components of the revenue requirements. In each of those electric jurisdictions, if the current year's revenue requirement is greater than the

revenue requirement reflected in that year's customer rates, an increase to electric operating revenues with an offset to a regulatory asset is recorded to reflect the expected recovery of those additional amounts from customers within the next two years. In each jurisdiction, if the current year's revenue requirement is less than the revenue requirement reflected in that year's customer rates, a reduction to electric operating revenues with an offset to a regulatory liability is recorded to reflect the expected refund to customers within the next two years. The increases or reductions to electric operating revenues are shown in base rates (estimate) and transmission services revenues, in the table above, for the electric delivery and electric transmission service revenues, respectively. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for information regarding Ameren Illinois' revenue requirement reconciliation pursuant to the IEIMA.

Ameren Illinois' electric margins increased $84 million, or 7%, in 2015 compared with 2014. The following items had a favorable effect on Ameren Illinois' electric margins:

•	Electric delivery service revenues that increased by $34 million, primarily because of increased rate base investment and higher recoverable costs under formula ratemaking pursuant to the IEIMA. These revenues were reduced by a lower return on equity for electric delivery service investments due to a reduction in the 30-year United States Treasury bond yields.

•	Transmission services revenues that increased by $29 million, due to a higher revenue requirement, driven primarily by increased rate base investment and recoverable costs under forward-looking formula ratemaking. These revenues were reduced by the recognition of a potential refund to customers based on the pending FERC complaint cases regarding the allowed base return on common equity.

•	A January 2015 ICC order regarding Ameren Illinois' cumulative power usage cost and its purchased power rider mechanism, which caused electric revenues to increase by $15 million compared with 2014.

Ameren Illinois' natural gas revenues decreased $193 million in 2015 compared with 2014 due to lower natural gas commodity prices and lower sales volumes due to weather. Ameren Illinois has a cost recovery mechanism for natural gas purchased on behalf of its customers. These pass-through purchased gas costs do not affect Ameren Illinois' natural gas margins, as any change in costs is offset by a corresponding change in revenues.

Ameren Illinois' natural gas margins decreased $18 million, or 4%, in 2015 compared with 2014. Winter temperatures in 2015 were warmer compared with 2014 as heating degree-days decreased 18%, which decreased margins by an estimated $10 million. The change in margins due to weather is the sum of the effect of weather (estimate) on revenues (-$72 million) and the effect of weather (estimate) on gas purchased for resale (+$62 million) in the table above.

2014 versus 2013

Ameren Corporation

Ameren's electric margins increased $147 million, or 4%, in 2014 compared with 2013. Ameren's natural gas margins increased $45 million, or 9%, in 2014 compared with 2013. These results were primarily driven by Ameren Missouri and Ameren Illinois results, as discussed below. Ameren's electric margins also reflect the results of operations of ATXI. ATXI’s transmission services revenues increased $14 million in 2014 compared with 2013 because of higher rate base investment and recoverable costs under forward-looking formula ratemaking. These revenues were reduced by the recognition of a potential refund to customers based on the pending November 2013 FERC complaint case regarding the allowed base return on common equity.

Ameren Missouri

Ameren Missouri's electric margins increased $35 million, or 1%, in 2014 compared with 2013. The following items had a favorable effect on Ameren Missouri's electric margins:

•	The absence of a charge in 2014 relating to a July 2013 MoPSC FAC prudence review order, which decreased 2013 revenues by $25 million. Ameren Missouri recorded a FAC prudence review charge in 2013 for its estimated obligation to refund to its electric customers the earnings associated with sales recognized by Ameren Missouri from October 1, 2009, to May 31, 2011.

•	Higher MEEIA net shared benefits driven by increased customer participation, which increased revenue by $15 million. Net shared benefits compensated Ameren Missouri for lower sales volumes from energy-efficiency-related volume reductions in current and future periods.

•	Winter temperatures in 2014 were colder compared with 2013, as heating degree-days increased 5%. The effect of weather increased margins by an estimated $3 million. The change in margins due to weather is the sum of the effect of weather on electric revenues (+$8 million) and the effect of weather on fuel and purchased power (-$5 million) in the table above.

Ameren Missouri's electric margins were unfavorably affected by lower sales volumes primarily caused by the MEEIA

programs. Lower sales volumes from energy-efficiency-related volume reductions were offset by MEEIA net shared benefits. Excluding the estimated effect of weather, total retail sales volumes decreased 1%, which decreased revenues by an estimated $22 million, partially offset by a decrease in net energy costs of $6 million. The decrease in net energy costs is the sum of the change in energy costs (+$18 million) and the change in off-system sales and transmission services revenues (-$12 million) in the table above.

Ameren Missouri's natural gas margins were comparable between the years.

Ameren Illinois

Ameren Illinois' electric margins increased $98 million, or 9%, in 2014 compared with 2013. The following items had a favorable effect on Ameren Illinois' electric margins:

•	Electric delivery service revenues that increased by $56 million, primarily because of increased rate base investment and higher recoverable costs under formula ratemaking pursuant to the IEIMA.

•

Transmission services revenues that increased by $10 million, largely because of a higher revenue requirement driven primarily by increased rate base investment and recoverable costs under forward-looking formula ratemaking. These revenues were reduced by the recognition of a potential refund to customers based on the pending November 2013 FERC complaint case regarding the allowed base return on common equity.

•	Excluding the estimated effect of weather, residential retail sales volumes that increased 1%, which increased revenues by $3 million.

Ameren Illinois' electric margins were unfavorably affected by summer temperatures in 2014 that were milder compared with 2013, as cooling degree-days decreased 6%, which decreased margins by an estimated $5 million.

Ameren Illinois' natural gas margins increased $44 million, or 11%, in 2014 compared with 2013. The following items had a favorable effect on Ameren Illinois' natural gas margins:

•	Higher natural gas delivery service rates effective January 2014, which increased revenues by an estimated $32 million.

•	Winter temperatures in 2014 were colder compared with 2013 as heating degree-days increased 6%. The effect of weather increased margins by an estimated $4 million. The change in margins due to weather is the sum of the effect of weather on revenues (+$32 million) and the effect of weather on gas purchased for resale (-$28 million) in the table above.

Other Operations and Maintenance Expenses

2015 versus 2014

Ameren Corporation

Other operations and maintenance expenses increased $10 million in 2015 compared with 2014. Other operations and maintenance expenses decreased $14 million at Ameren Missouri and increased $26 million at Ameren Illinois.

Ameren Missouri

Other operations and maintenance expenses were $14 million lower in 2015 compared with 2014. The following items decreased other operations and maintenance expenses between years:

•	A reduction of $27 million in refueling and maintenance

outage costs at the Callaway energy center, primarily due to costs for the 2014 scheduled outage. Costs for the 2014 scheduled outage were $36 million. There was no refueling outage scheduled in 2015; however, $9 million in preparation costs were incurred in 2015 for the 2016 scheduled outage.

•	A decrease of $9 million in employee benefit costs, primarily due to a change in pension and postretirement expenses allowed in rates, as a result of the April 2015 MoPSC electric rate order. Electric revenues from customer billings decreased by a corresponding amount, with no overall effect on net income.

•	A reduction of $8 million in disposal costs for low-level radioactive nuclear waste.

•	A decrease of $6 million in energy center maintenance costs, primarily due to reduced major outages at coal-fired energy centers.

•	A decrease of $3 million in bad debt expense due to improved customer collections.

The following items increased other operations and maintenance expenses between years:

•	Amortization of $17 million in previously deferred solar rebate costs, as a result of the April 2015 MoPSC electric rate order. Electric revenues from customer billings increased by a corresponding amount, with no overall effect on net income.

•	An increase of $16 million in MEEIA energy efficiency program costs in 2015 due to program enhancements and increased customer participation. Electric revenues from customer billings increased by a corresponding amount, with no overall effect on net income.

•	An increase of $3 million due to an unrealized MTM loss in 2015 compared with a gain in 2014, resulting from changes in the market value of investments used to support Ameren’s deferred compensation plans.

•	An increase of $2 million in electric distribution maintenance expenditures, primarily related to increased system repair work.

Ameren Illinois

Pursuant to the provisions of the IEIMA's and the FERC's formula rate frameworks, recoverable electric service costs that are not recovered through separate cost recovery mechanisms are included in Ameren Illinois’ revenue requirement reconciliations, which result in corresponding adjustments to electric operating revenues, with no overall effect on net income. These recoverable electric service costs include other operations and maintenance expenses, depreciation and amortization, taxes other than income taxes, interest charges, and income taxes.

Other operations and maintenance expenses were $26 million higher in 2015 compared with 2014. The following items increased other operations and maintenance expenses between years:

•	An increase of $8 million in bad debt, customer energy efficiency, and environmental remediation costs. These

expenses are included in cost riders that result in additional electric and natural gas revenues, resulting in no overall effect on net income.

•	An increase of $7 million in electric delivery maintenance expenditures, primarily related to increased circuit maintenance and system repair work as a result of regulatory compliance requirements.

•	An increase of $7 million in labor costs, primarily because of staff additions to meet enhanced reliability standards and customer service goals related to the IEIMA and wage increases.

•	An increase of $3 million in storm-related repair costs.

•	An increase of $3 million in employee benefit costs, primarily due to higher pension and postretirement expenses caused by changes in actuarial assumptions and the performance of plan assets.

•	An increase of $2 million due to an unrealized MTM loss in 2015 compared with a gain in 2014, resulting from changes in the market value of investments used to support Ameren’s deferred compensation plans.

2014 versus 2013

Ameren Corporation

Other operations and maintenance expenses increased $73 million in 2014 compared with 2013. Other operations and maintenance expenses increased $30 million at Ameren Missouri and increased $78 million at Ameren Illinois. Partially offsetting the increases at Ameren Missouri and Ameren Illinois were decreased corporate expenses between years of $35 million, primarily due to the substantial elimination of business and administrative costs previously incurred in support of the divested merchant generation business.

Ameren Missouri

Other operations and maintenance expenses were $30 million higher in 2014 compared with 2013. The following items increased other operations and maintenance expenses between years:

•	An increase of $17 million in labor costs, primarily because of wage increases.

•	An increase of $14 million in litigation and asbestos claim costs due to several legal proceedings.

•	An increase of $8 million in disposal costs for low-level radioactive nuclear waste at the Callaway energy center.

•	An increase of $7 million in MEEIA energy efficiency program costs in 2014 due to increased customer participation.

•	A reduction of $3 million in unrealized net MTM gains, resulting from changes in the market value of investments used to support Ameren’s deferred compensation plans.

The following items decreased other operations and maintenance expenses between years:

•	A reduction of $13 million in energy center costs, primarily related to coal handling.

•	A decrease of $7 million in storm-related costs due to fewer major storms in 2014.

•	A reduction of $2 million in refueling and maintenance costs associated with the scheduled Callaway outages. The 2014 outage costs were $36 million compared with 2013 outage costs of $38 million.

Ameren Illinois

Other operations and maintenance expenses were $78 million higher in 2014 compared with 2013. The following items increased other operations and maintenance expenses between years:

•	An increase of $29 million in bad debt, customer energy efficiency, and environmental remediation costs.

•	An increase of $17 million in labor costs, primarily because of staff additions to meet enhanced reliability standards and customer service goals related to the IEIMA and wage increases.

•	An increase of $13 million in electric delivery maintenance expenditures, primarily related to increased system repair and vegetation management work.

•	An increase of $8 million in asbestos claim costs.

•	An increase of $7 million in information technology service expenses, partially related to the IEIMA implementation.

•	An increase of $6 million in natural gas compliance expenditures, primarily related to pipeline integrity work.

•	An increase of $4 million in rental expense, primarily related to software from affiliated companies.

•	A reduction of $2 million in unrealized net MTM gains, resulting from changes in the market value of investments used to support Ameren’s deferred compensation plans.

Other operations and maintenance expenses decreased between years because of a reduction in employee benefit costs of $12 million, primarily due to lower pension and postretirement expenses caused by changes in actuarial assumptions and the performance of plan assets.

Provision for Callaway Construction and Operating License

Primarily because of changes in vendor support for licensing efforts at the NRC, Ameren Missouri’s assessment of long-term capacity needs, declining costs of alternative generation technologies, and the regulatory framework in Missouri, Ameren Missouri discontinued its efforts to license and build a second nuclear unit at its existing Callaway energy center site in 2015. As a result of this decision, Ameren and Ameren Missouri recognized a $69 million noncash pretax provision for all of the previously capitalized COL costs. See Note 2 – Rate and Regulatory Matters under Part II, Item 8 of this report for additional information.

Depreciation and Amortization

2015 versus 2014

Ameren Corporation

Depreciation and amortization expenses increased $51 million in 2015 compared with 2014, primarily because of increased expenses at Ameren Missouri and Ameren Illinois, as discussed below.

Ameren Missouri

Depreciation and amortization expenses increased $19 million, primarily because of multiple significant electric projects completed in 2014 and increased depreciation rates resulting from the April 2015 MoPSC electric rate order.

Ameren Illinois

Depreciation and amortization expenses increased $32 million, primarily because of electric system capital additions and amortization of natural gas-related investments.

2014 versus 2013

Ameren Corporation

Depreciation and amortization expenses increased $39 million in 2014 compared with 2013, primarily because of increased expenses at Ameren Missouri and Ameren Illinois, as discussed below.

Ameren Missouri

Depreciation and amortization expenses increased $19 million, primarily because of electric system capital additions.

Ameren Illinois

Depreciation and amortization expenses increased $20 million, primarily because of electric system capital additions.

Taxes Other Than Income Taxes

2015 versus 2014

Ameren Corporation

Taxes other than income taxes increased $5 million in 2015 compared with 2014, primarily because of increased expenses at Ameren Missouri, partially offset by decreased expenses at Ameren Illinois, as discussed below. See Excise Taxes in Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report for additional information.

Ameren Missouri

Taxes other than income taxes increased $13 million, primarily because of increased property taxes resulting from both higher tax rates and assessed property tax values, and increased gross receipts taxes resulting from higher electric service rates. The gross receipts tax increase had no effect on net income as electric revenues for gross receipts taxes from customer billings increased by a corresponding amount.

Ameren Illinois

Taxes other than income taxes decreased $8 million, primarily because of decreased gross receipts taxes resulting from lower natural gas sales prices and volumes. Natural gas revenues for gross receipts taxes from customer billings decreased by a corresponding amount, with no overall effect on net income.

2014 versus 2013

Ameren Corporation

Taxes other than income taxes increased $10 million in 2014 compared with 2013, primarily because of increased expenses at Ameren Missouri and Ameren Illinois, as discussed below.

Ameren Missouri

Taxes other than income taxes increased $3 million, primarily because of an increase in property taxes resulting from higher tax rates and increased state and local assessments in 2014.

Ameren Illinois

Taxes other than income taxes increased $6 million because of a $3 million increase in gross receipts taxes, as a result of higher natural gas rates and higher sales volumes, and because of a $3 million increase in property taxes between years.

Other Income and Expenses

2015 versus 2014

Ameren Corporation

Other income, net of expenses, decreased $13 million in 2015 compared with 2014, primarily because of a $5 million increase in charitable contributions at Ameren (parent) due to timing of contributions, and items at Ameren Missouri, as discussed below. See Note 6 – Other Income and Expenses under Part II, Item 8, of this report for additional information.

Ameren Missouri

Other income, net of expenses, decreased $7 million, primarily because of a decrease in the allowance for equity funds used during construction, as multiple significant electric capital projects were completed in 2014.

Ameren Illinois

Other income, net of expenses, was comparable between years.

2014 versus 2013

Ameren Corporation

Other income, net of expenses, increased $14 million in 2014 compared with 2013, primarily because of a $4 million reduction in charitable contributions at Ameren (parent) due to the timing of contributions, an increase in Ameren (parent) interest income from a note receivable with Marketing Company, and items at Ameren Illinois, as discussed below.

Ameren Missouri

Other income, net of expenses, was comparable between years.

Ameren Illinois

Other income, net of expenses, increased $8 million, primarily because of increased income from customer-requested construction, and increased interest income on both the IEIMA 2013 and 2014 revenue requirement reconciliation regulatory assets. A decrease in the equity portion of allowance for funds used during construction, primarily due to increased usage of short-term debt to fund capital expenditures, reduced the favorable effect of the above items.

Interest Charges

2015 versus 2014

Ameren Corporation

Interest charges increased $14 million in 2015 compared with 2014. Interest charges at Ameren (parent) decreased by $13 million, primarily because of a lower average interest rate on debt in 2015. In May 2014, Ameren (parent) repaid at maturity $425 million of senior unsecured notes, with proceeds from commercial paper issuances. In November 2015, Ameren (parent) issued $700 million of senior unsecured notes, the proceeds of which were used to repay commercial paper borrowings. The interest charges reduction at Ameren (parent) was offset, in part, by increases in interest charges at Ameren Missouri and Ameren Illinois, as discussed below.

Ameren Missouri

Interest charges increased $8 million, primarily because of a decrease in the allowance for funds used during construction, as multiple significant electric projects were completed in 2014, and because of the issuance of senior secured notes in April 2015.

Ameren Illinois

Interest charges increased $19 million, because of the issuances of senior secured notes in June 2014 and December 2014, the proceeds of which were used to repay commercial paper borrowings, and the absence in 2015 of an $11 million reduction from an ICC electric rate order received in December 2014, which partially reversed a charge recorded in 2013 that had disallowed the recovery from customers of certain debt premium costs.

2014 versus 2013

Ameren Corporation

Interest charges decreased $57 million in 2014 compared with 2013, primarily because of a $24 million reduction in interest charges at Ameren (parent), as a result of the maturity of $425 million of 8.875% senior unsecured notes in May 2014, which was replaced with lower cost commercial paper, and a decrease in interest charges associated with uncertain tax positions at Ameren (parent). Additionally, interest charges were lower at Ameren Illinois, as discussed below.

Ameren Missouri

Interest charges were comparable between years. The absence in 2014 of a 2013 reduction to interest charges associated with uncertain tax positions resulted in higher interest charges. See Note 13 – Income Taxes under Part II, Item 8, of this report for information regarding uncertain tax positions. This increase was partially offset by the effect of refinancing activities that resulted in higher-cost debt being replaced with lower-cost debt.

Ameren Illinois

Interest charges decreased $31 million. There was a reduction in interest charges associated with the regulatory liability for the 2012 IEIMA revenue requirement reconciliation as the refund obligation was completed throughout 2014. The 2013 and 2014 IEIMA revenue requirement reconciliations were both regulatory assets, which, as discussed above under Other Income and Expenses, resulted in interest income. Also, the favorable effect of refinancing activities that resulted in higher-cost debt being replaced with lower-cost debt also decreased interest charges. Additionally, the ICC issued an electric rate order in December 2014, which resulted in a partial reversal of a charge recorded in 2013 associated with a December 2013 ICC electric rate order that had disallowed the recovery from customers of certain debt premium costs. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information.

Income Taxes

The following table presents effective income tax rates for the years ended December 31, 2015, 2014, and 2013:

	2015	2014	2013
Ameren	38%	39%	38%
Ameren Missouri	37%	37%	38%
Ameren Illinois	37%	41%	40%

See Note 13 – Income Taxes under Part II, Item 8, of this report for information regarding reconciliations of effective income tax rates.

Income (Loss) from Discontinued Operations, Net of Taxes

In 2015, based on completion of the IRS audit of Ameren’s 2013 tax year, Ameren recognized a tax benefit of $53 million due to the resolution of an uncertain tax position from discontinued operations. No material activity was recorded associated with discontinued operations in 2014. During the year ended December 31, 2013, the loss from discontinued operations, net of taxes, was primarily related to the impairment loss and related income tax effects associated with the New AER divestiture. See Note 16 – Divestiture Transactions and Discontinued Operations under Part II, Item 8, of this report for additional information.

LIQUIDITY AND CAPITAL RESOURCES

Our tariff-based gross margins are our principal source of cash from operating activities. A diversified retail customer mix, primarily consisting of rate-regulated residential, commercial, and industrial customers, provides us with a reasonably

predictable source of cash. In addition to using cash generated from operating activities, we use available cash, borrowings under the Credit Agreements, commercial paper issuances, money pool borrowings, or, in the case of Ameren Missouri and Ameren Illinois, other short-term borrowings from affiliates to support normal operations and temporary capital requirements. We may reduce our short-term borrowings with cash from operations or, at our discretion, with long-term borrowings, or, in the case of Ameren Missouri and Ameren Illinois, with capital contributions from Ameren (parent). We expect to make significant capital expenditures over the next five years as we invest in our electric and natural gas utility infrastructure to support overall system reliability, environmental compliance, and other improvements. We intend to fund those capital expenditures with available cash on hand, cash generated from operating activities, and commercial paper and debt issuances so that we maintain an equity ratio around 50%, assuming constructive regulatory environments.

The use of cash from operating activities and short-term borrowings to fund capital expenditures and other long-term investments may periodically result in a working capital deficit, defined as current liabilities exceeding current assets, as was the case at December 31, 2015, for Ameren. Ameren's working capital deficit was primarily the result of current maturities of long-term debt and commercial paper issuances. With the Credit Agreements and cash and cash equivalents available, the Ameren Companies had access to $1.8 billion of credit capacity available and $2.1 billion of liquidity at December 31, 2015.

The following table presents net cash provided by (used in) operating, investing and financing activities for the years ended December 31, 2015, 2014, and 2013:

	Net Cash Provided By (Used In) Operating Activities												Net Cash Provided by (Used In) Investing Activities												Net Cash Provided by (Used In) Financing Activities
	2015				2014				2013				2015				2014				2013				2015				2014				2013
Ameren(a) – continuing operations	$	2,021			$	1,557			$	1,636			$	(1,951	)		$	(1,856	)		$	(1,440	)		$	246			$	141			$	(149	)
Ameren(a) – discontinued operations	(4		)		(6		)		57				(25		)		139				(283		)		—				—				—
Ameren Missouri	1,247				950				1,143				(724		)		(837		)		(687		)		(325		)		(113		)		(603		)
Ameren Illinois	763				445				651				(913		)		(828		)		(695		)		220				383				45

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Cash Flows from Operating Activities

2015 versus 2014

Ameren Corporation

Ameren’s cash from operating activities associated with continuing operations increased $464 million in 2015, compared with 2014. The following items contributed to the increase:

•	A $192 million increase resulting from electric and natural gas margins, as discussed in Results of Operations, excluding certain noncash items, as well as the change in customer receivable balances.

•	A $149 million increase in net energy costs collected from Ameren Missouri customers under the FAC.

•	A $137 million increase in cash associated with Ameren Illinois' IEIMA revenue requirement reconciliation adjustments, as Ameren Illinois collected $69 million from customers in 2015 and refunded $68 million to customers in 2014.

•	A $57 million decrease in Ameren Missouri rebate payments provided for customer-installed solar generation as the rebate program was substantially completed by the end of 2014.

•	A $33 million increase in natural gas commodity costs collected from customers under the PGAs, primarily related to Ameren Illinois.

•	A $31 million decrease in the cost of natural gas held in storage caused primarily by lower gas prices.

•	A $19 million decrease in payments for nuclear refueling and maintenance outages at the Ameren Missouri Callaway energy center. There was no refueling and maintenance outage in 2015; however, there were cash expenditures related to the 2016 spring outage made in 2015.

The following items partially offset the increase in Ameren's cash from operating activities associated with continuing operations during 2015, compared to 2014:

•	A $49 million increase in coal inventory costs at Ameren Missouri caused by increased volumes resulting from the absence of weather-related railroad delivery delays that occurred in 2014.

•	A net $29 million decrease in returns of collateral posted with counterparties, primarily resulting from changes in the market prices of power and natural gas and in contracted commodity volumes, partially offset by the effect of credit rating upgrades.

•	A $24 million decrease in income tax refunds primarily due to the absence in 2015 of tax settlements pertaining to 2007 through 2011 that were received in 2014. See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report for income tax refund information.

•	A $24 million increase in pension and postretirement benefit plan contributions caused by a change in actuarial assumptions.

•	A $7 million increase in property tax payments at Ameren Missouri caused by both higher assessed property tax values and tax rates.

•	A $7 million increase in expenditures for customer energy efficiency programs compared with amounts collected from Ameren Illinois customers.

Ameren’s cash from operating activities associated with discontinued operations was comparable between 2015 and 2014.

Ameren Missouri

Ameren Missouri’s cash from operating activities increased $297 million in 2015, compared with 2014. The following items contributed to the increase:

•	A $149 million increase in net energy costs collected from customers under the FAC.

•	A $143 million decrease in income taxes paid to Ameren (parent) pursuant to the tax allocation agreement, primarily related to a change in the tax treatment for generation repairs adopted in 2013, which increased payments in 2014.

•	A $57 million decrease in rebate payments provided for customer-installed solar generation as the rebate program was substantially completed by the end of 2014.

•	A $37 million increase resulting from electric and natural gas margins, as discussed in Results of Operations, excluding certain noncash items, as well as the change in customer receivable balances.

•	A $19 million decrease in payments for scheduled nuclear refueling and maintenance outages at the Callaway energy center. There was no refueling and maintenance outage in 2015; however, there were cash expenditures related to the 2016 spring outage made in 2015.

The following items partially offset the increase in Ameren Missouri's cash from operating activities during 2015, compared to 2014:

•	A $49 million increase in coal inventory costs caused by increased volumes resulting from the absence of weather-related railroad delivery delays that occurred in 2014.

•	A net $12 million decrease in returns of collateral posted with counterparties, primarily resulting from changes in the market prices of power and natural gas and in contracted commodity volumes, partially offset by the effect of credit rating upgrades.

•	An $11 million increase in pension and postretirement benefit plan contributions caused by a change in actuarial assumptions.

•	A $7 million increase in property tax payments caused by both higher assessed property tax values and tax rates.

Ameren Illinois

Ameren Illinois’ cash from operating activities increased $318 million in 2015, compared with 2014. The following items contributed to the increase:

•	A $137 million increase in cash associated with IEIMA revenue requirement reconciliation adjustments, as $69 million was collected from customers in 2015 and $68 million was refunded to customers in 2014.

•	A $101 million increase resulting from electric and natural gas margins, as discussed in Results of Operations, excluding certain noncash items, as well as the change in customer receivable balances.

•	A $69 million increase in income taxes refunds, pursuant to the tax allocation agreement with Ameren (parent), primarily related to deductions for accelerated depreciation and increased capital expenditures.

•	A $31 million increase in natural gas commodity costs collected from customers under the PGA.

•	A $26 million decrease in the cost of natural gas held in storage caused primarily by lower gas prices.

The following items partially offset the increase in Ameren Illinois’ cash from operating activities during 2015, compared with 2014:

•	A net $17 million decrease in returns of collateral posted with counterparties, primarily resulting from changes in the market prices of power and natural gas and in contracted commodity volumes, partially offset by the effect of credit rating upgrades.

•	A $12 million increase in pension and postretirement benefit plan contributions caused by a change in actuarial assumptions.

•	A $7 million increase in expenditures for customer energy efficiency programs compared with amounts collected from customers.

2014 versus 2013

Ameren Corporation

Ameren’s cash from operating activities associated with continuing operations decreased $79 million in 2014, compared with 2013. The following items contributed to the decrease:

•	An $89 million decrease in the cash associated with Ameren Missouri’s under-recovered FAC costs. Deferrals and refunds exceeded recoveries in 2014 by $49 million, while recoveries exceeded deferrals in 2013 by $40 million.

•	The 2014 refunds to Ameren Illinois customers of $67 million as required under the provisions of the IEIMA for the 2012 revenue requirement reconciliation adjustment, compared with no refunds in 2013.

•	A $65 million difference in expenditures for customer energy efficiency programs compared with amounts collected from Ameren Missouri and Ameren Illinois customers.

•	A $50 million increase in coal purchases caused by increased volumes and prices. Ameren Missouri purchased less coal in 2013 due, in part, to delivery disruptions from flooding.

•	A $42 million difference in purchased power commodity costs incurred compared with amounts collected from Ameren Illinois' customers.

•	A $39 million increase in rebate payments provided for customer-installed solar generation at Ameren Missouri.

•	A $38 million decrease in natural gas commodity costs collected from customers under the PGAs, primarily related to Ameren Illinois.

•	A decrease of $26 million at Ameren Missouri and Ameren Illinois for storm restoration assistance provided to nonaffiliated utilities, primarily due to Hurricane Sandy in 2013.

•	A $26 million increase in payments to contractors at Ameren Illinois for additional reliability, maintenance, and IEIMA projects.

•	Refunds of $24 million to customers as required by a September 2014 FERC order in Ameren Illinois' wholesale distribution rate case.

•	A $23 million increase in the value of natural gas held in storage at Ameren Illinois because of increased market prices and timing of injections and withdrawals.

•	A $22 million decrease associated with stock-based compensation awards.

•	A $21 million increase in labor costs at Ameren Illinois, primarily because of wage increases and staff additions to meet enhanced reliability and customer service goals related to the IEIMA.

•	A $21 million difference in transmission service costs incurred compared with amounts collected from customers, primarily at Ameren Illinois.

•	A net $19 million decrease in returns of collateral posted with counterparties due to changes at Ameren Missouri and Ameren Illinois discussed below.

•	A $17 million increase in the purchase of receivables from alternative retail electric suppliers compared with amounts collected from Ameren Illinois customers.

•	A $16 million decrease in contributions received by Ameren Illinois from customers for future construction.

•	An $8 million increase in property tax payments at Ameren Missouri caused by higher assessed property tax values and increased property tax rates.

The following items partially offset the decrease in Ameren's cash from operating activities associated with continuing operations during 2014, compared with 2013:

•	A $240 million increase resulting from electric and natural gas margins, as discussed in Results of Operations, excluding certain noncash items, as well as the change in customer receivable balances.

•	Income tax refunds of $41 million in 2014, primarily due to federal settlements for the tax years 2007 through 2011, compared with income tax payments in 2013 of $116 million. See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report for income tax payment (refund) information.

•	A $76 million decrease in pension and postretirement benefit plan contributions. In addition to the Ameren Missouri and Ameren Illinois amounts discussed below, Ameren's nonregistrant subsidiaries' contributions to the pension and postretirement benefit plans decreased $30 million.

•	A $29 million decrease in interest payments, primarily due to refinancing activity at Ameren Missouri and Ameren (parent). See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report for interest payment information as it relates to continuing and discontinued operations.

•	A $27 million insurance receipt in 2013 at Ameren Missouri related to the December 2005 breach of the upper reservoir at the Taum Sauk pumped-storage hydroelectric energy center.

Ameren’s cash from operating activities associated with discontinued operations decreased in 2014, compared with 2013. The 2013 activity related to the disposed New AER and the Elgin, Gibson City and Grand Tower energy centers. The 2014 activity related to transaction costs and tax payments associated with the Elgin, Gibson City, and Grand Tower energy centers.

Ameren Missouri

Ameren Missouri’s cash from operating activities decreased $193 million in 2014, compared with 2013. The following items contributed to the decrease:

•	A $129 million increase in income tax payments paid to Ameren (parent) pursuant to the tax allocation agreement, resulting primarily from fewer deductions for capital expenditures for tax years 2007 through 2013, which caused increased payments in 2014. The increase was partially

offset by a reduction in payments due to the use of net operating loss carryforwards in 2014.

•	An $89 million decrease in the cash associated with Ameren Missouri’s under-recovered FAC costs. Deferrals and refunds exceeded recoveries in 2014 by $49 million, while recoveries exceeded deferrals in 2013 by $40 million.

•	A $50 million increase in coal purchases caused by increased volumes and prices. Ameren Missouri purchased less coal in 2013, due, in part, to delivery disruptions from flooding.

•	A $39 million increase in rebate payments provided for customer-installed solar generation.

•	A $28 million difference in expenditures for customer energy efficiency programs compared with amounts collected from customers.

•	An $11 million decrease in natural gas commodity costs collected from customers under the PGA.

•	A decrease of $10 million for storm restoration assistance provided to nonaffiliated utilities, primarily related to Hurricane Sandy in 2013.

•	An $8 million increase in property tax payments caused by higher assessed property tax values and increased property tax rates.

The following items partially offset the decrease in Ameren Missouri's cash from operating activities during 2014, compared with 2013:

•	A $96 million increase resulting from electric and natural gas margins, as discussed in Results of Operations, excluding certain noncash items, as well as the change in customer receivable balances.

•	A $27 million insurance receipt in 2013 related to the December 2005 breach of the upper reservoir at the Taum Sauk pumped-storage hydroelectric energy center.

•	A $26 million decrease in pension and postretirement benefit plan contributions.

•	A net $10 million increase in returns of collateral posted with counterparties primarily resulting from changes in the market prices of power and natural gas and in contracted commodity volumes.

•	A $9 million decrease in interest payments, primarily due to refinancing activity.

Ameren Illinois

Ameren Illinois’ cash from operating activities decreased $206 million in 2014, compared with 2013. The following items contributed to the decrease:

•	The 2014 refunds to customers of $67 million as required under the provisions of the IEIMA for the 2012 revenue requirement reconciliation adjustment, compared with no refunds in 2013.

•	A $42 million difference in purchased power commodity costs incurred compared with amounts collected from customers.

•	A $37 million difference in expenditures for customer energy efficiency programs compared with amounts collected from customers.

•	A net $29 million decrease in returns of collateral posted with counterparties, primarily resulting from changes in the market prices of power and natural gas and in contracted commodity volumes.

•	A $27 million decrease in natural gas commodity costs collected from customers under the PGA.

•	A $26 million increase in payments to contractors for additional reliability, maintenance, and IEIMA projects.

•	Refunds to customers of $24 million as required by a September 2014 FERC order in the wholesale distribution rate case.

•	A $23 million increase in the value of natural gas held in storage because of increased market prices and the timing of injections and withdrawals.

•	A $21 million increase in labor costs, primarily because of wage increases and staff additions to meet enhanced reliability and customer service goals related to the IEIMA.

•	A $20 million difference in transmission service costs incurred compared with amounts collected from customers.

•	A $17 million increase in the purchase of receivables from alternative retail electric suppliers compared with amounts collected from customers.

•	A $16 million decrease in contributions received from customers for future construction.

•	The absence of $16 million received in 2013 for storm restoration assistance provided to nonaffiliated utilities, primarily due to Hurricane Sandy.

The following items partially offset the decrease in Ameren Illinois' cash from operating activities during 2014, compared with 2013:

•	Electric and natural gas margins, as discussed in Results of Operations excluding certain noncash items, that increased by $126 million.

•	A $21 million increase in income tax refunds from Ameren (parent) pursuant to the tax allocation agreement, resulting primarily from the expected use of net operating loss carryforwards in 2014.

•	A $20 million decrease in pension and postretirement benefit plan contributions.

Pension Plans

Ameren’s pension plans are funded in compliance with income tax regulations, federal funding, and other regulatory requirements. As a result, Ameren expects to fund its pension plans at a level equal to the greater of the pension expense or the legally required minimum contribution. Considering Ameren’s assumptions at December 31, 2015, its investment performance in 2015, and its pension funding policy, Ameren expects to make annual contributions of $40 million to $70 million in each of the next five years, with aggregate estimated contributions of $280 million. We expect Ameren Missouri’s and Ameren Illinois’ portions of the future funding requirements to be 40% and 50%, respectively. These amounts are estimates. The estimates may

change with actual investment performance, changes in interest rates, changes in our assumptions, changes in government regulations, or any voluntary contributions. In 2015, Ameren contributed $111 million to its pension plans. See Note 11 – Retirement Benefits under Part II, Item 8, of this report for additional information.

Cash Flows from Investing Activities

2015 versus 2014

Ameren's cash used in investing activities associated with continuing operations increased by $95 million during 2015, compared with 2014. Capital expenditures increased $132 million, because of increased transmission expenditures, which included a $174 million increase for ATXI primarily related to the Illinois Rivers project, and increased Ameren Illinois capital expenditures partially offset by decreased expenditures at Ameren Missouri.

During 2015, Ameren’s cash used in investing activities associated with discontinued operations consisted of a $25 million payment for a liability associated with the New AER divestiture. During 2014, cash provided by investing activities associated with Ameren’s discontinued operations consisted of $152 million received from Rockland Capital for the sale of the Elgin, Gibson City, and Grand Tower gas-fired energy centers in January 2014, offset by payment of $13 million to IPH for the final working capital adjustment and certain liabilities associated with the New AER divestiture.

Ameren Missouri’s cash used in investing activities decreased by $113 million during 2015, compared with 2014. Capital expenditures decreased $125 million, primarily because several large projects were completed in 2014. Nuclear fuel expenditures decreased by $22 million because of the timing of purchases in 2015 compared with 2014. In addition, cash used in investing activities increased in 2015 because of net advances to the money pool of $36 million; there were no advances in 2014.

Ameren Illinois’ cash used in investing activities increased by $85 million during 2015, compared with 2014, because of increased capital expenditures, primarily for reliability, IEIMA projects, and transmission.

2014 versus 2013

Ameren's cash used in investing activities associated with continuing operations increased by $416 million during 2014, compared with 2013. Capital expenditures increased $406 million, primarily because of increased transmission expenditures, which included a $150 million increase for ATXI's Illinois Rivers project. In addition, capital expenditures for energy center, reliability and IEIMA projects increased cash used in investing activities and are discussed below.

During 2014, cash provided by investing activities associated with Ameren’s discontinued operations consisted of $152 million received from Rockland Capital for the sale of the Elgin, Gibson City, and Grand Tower gas-fired energy centers in

January 2014, offset by payment of $13 million to IPH for the final working capital adjustment and a portion of certain liabilities associated with the New AER divestiture. In comparison, cash used in investing activities associated with discontinued operations during 2013 was $283 million, primarily because of the requirement to leave $235 million with New AER upon divestiture, pursuant to the transaction agreement with IPH.

Ameren Missouri’s cash used in investing activities increased by $150 million during 2014, compared with 2013. Capital expenditures increased $99 million, primarily for reliability and energy center projects, including the nuclear reactor vessel head replacement project at its Callaway energy center, the electrostatic precipitator upgrades at the Labadie energy center, a new substation in St. Louis, and investment in the O’Fallon energy center, offset by a reduction in storm restoration expenditures. Nuclear fuel expenditures increased by $29 million because of the timing of purchases in 2014 compared with 2013. In addition, cash used in investing activities increased in 2014 because of the absence in 2014 of $24 million in net receipts related to money pool advances received in 2013.

Ameren Illinois' cash used in investing activities increased $133 million during 2014, compared with 2013, because of increased capital expenditures, primarily for transmission, reliability, and IEIMA projects.

Capital Expenditures

The following table presents the capital expenditures by the Ameren Companies for the years ended December 31, 2015, 2014, and 2013:

	2015				2014				2013
Ameren(a)	$	1,917			$	1,785			$	1,379
Ameren Missouri	622				747				648
Ameren Illinois	918				835				701

(a)	Includes amounts for Ameren registrant and nonregistrant subsidiaries and the elimination of intercompany transfers.

Ameren’s 2015 capital expenditures consisted of expenditures made by its subsidiaries including ATXI, which spent $375 million primarily on the Illinois Rivers project. Ameren Illinois spent $288 million on transmission projects and $134 million on IEIMA projects. Other capital expenditures were made principally to maintain, upgrade, and improve the reliability of the transmission and distribution systems of Ameren Missouri and Ameren Illinois as well as to fund various Ameren Missouri energy center upgrades.

Ameren’s 2014 capital expenditures consisted of expenditures made by its subsidiaries including ATXI, which spent $201 million on the Illinois Rivers project. Ameren Missouri spent $101 million for electrostatic precipitator upgrades at its Labadie energy center, $33 million for the replacement of the nuclear reactor vessel head at its Callaway energy center, and $16 million for the construction of the O’Fallon energy center. Ameren Illinois spent $284 million on transmission initiatives and $89 million on IEIMA projects. Other capital expenditures were made principally to maintain, upgrade, and improve the reliability

of the transmission and distribution systems of Ameren Missouri and Ameren Illinois, as well as to fund various Ameren Missouri energy center upgrades.

Ameren’s 2013 capital expenditures consisted of expenditures made by its subsidiaries including ATXI, which spent $51 million on the Illinois Rivers project. Ameren Missouri spent $53 million for electrostatic precipitator upgrades at the Labadie energy center, $30 million on storm restoration, and $29 million on the replacement of the nuclear reactor vessel head at its Callaway energy center which was installed during the 2014 refueling and maintenance outage. Ameren Illinois spent $269 million on transmission initiatives, $33 million on IEIMA projects, and $23 million on storm restoration. Other capital expenditures were made principally to maintain, upgrade, and improve the reliability of the transmission and distribution systems of Ameren Missouri and Ameren Illinois as well as to fund various Ameren Missouri energy center upgrades.

In December 2015, a federal tax law was enacted that authorized the continued use of bonus depreciation that allows for an acceleration of deductions for tax purposes. Bonus depreciation is expected to increase cash flow through at least 2020. Ameren expects to use this incremental cash flow to make capital investments in utility infrastructure for the benefit of its customers. Without these investments, the bonus depreciation would reduce rate base, which would reduce our revenue requirements and future earnings growth. The impact of bonus depreciation on Ameren Missouri, Ameren Illinois, and ATXI will vary based on investment levels at each company.

The following table presents Ameren's estimate of capital expenditures that will be incurred from 2016 through 2020, including construction expenditures, allowance for funds used during construction, and expenditures for compliance with existing environmental regulations. Ameren expects to allocate more of its capital expenditures to Ameren Illinois and ATXI based, in part, on the more constructive regulatory frameworks within which they operate. These estimates do not include the impacts of the Clean Power Plan. See Note 15 – Commitments and Contingencies under Part II, Item 8, of this report for additional information regarding the Clean Power Plan.

	2016				2017 - 2020								Total
Ameren Missouri	$	835			$	3,095		-	$	3,420			$	3,930		-	$	4,255
Ameren Illinois	905				4,820			-	5,325				5,725			-	6,230
ATXI	410				565			-	625				975			-	1,035
Other	5				10			-	15				15			-	20
Ameren	$	2,155			$	8,490		-	$	9,385			$	10,645		-	$	11,540

Ameren Missouri’s estimated capital expenditures include transmission, distribution, and generation-related investments, as well as expenditures for compliance with environmental regulations. Ameren Illinois’ estimated capital expenditures are primarily for electric and natural gas transmission and distribution-related investments, capital expenditures to modernize its distribution system pursuant to the IEIMA, and capital expenditures for qualified investments in natural gas infrastructure under the QIP rider. ATXI's estimated capital

expenditures include expenditures for the three MISO-approved multi-value transmission projects. For additional information regarding the IEIMA capital expenditure requirements, the QIP rider, and ATXI's transmission projects, see Part I, Item 1, of this report.

Ameren Missouri continually reviews its generation portfolio and expected power needs. As a result, Ameren Missouri could modify its plan for generation capacity, the type of generation asset technology that will be employed, and whether capacity or power may be purchased, among other changes. Additionally, we continually review the reliability of our transmission and distribution systems, expected capacity needs, and opportunities for transmission investments. The timing and amount of investments could vary because of changes in expected capacity, the condition of transmission and distribution systems, and our ability and willingness to pursue transmission investments, among other factors. Any changes in future generation, transmission, or distribution needs could result in significant capital expenditures or losses, which could be material. Compliance with environmental regulations could also have significant impacts on the level of capital expenditures.

Environmental Capital Expenditures

Ameren Missouri will incur significant costs in future years to comply with federal and state regulations including those requiring the reduction of SO2, NOx, mercury, and CO2 emissions from its coal-fired energy centers. See Note 15 – Commitments and Contingencies under Part II, Item 8, of this report for a discussion of existing environmental laws and regulations that affect, or may affect, our facilities and capital expenditures to comply with such laws and regulations.

Cash Flows from Financing Activities

2015 versus 2014

Ameren's financing activities associated with continuing operations provided net cash of $246 million in 2015, compared with $141 million in 2014. During 2015, Ameren (parent) received proceeds of $700 million from long-term debt issuances and repaid short-term debt in addition to the activity at Ameren Missouri and Ameren Illinois to fund maturities of long-term debt and repay short-term debt discussed below. In 2015, the issuances of long-term debt, net of repayments for short-term debt and for long-term debt at maturity, along with cash provided by operating activities were used to fund investing activities and pay dividends. In comparison, during 2014, Ameren and its registrant subsidiaries issued long-term and short-term debt to fund the maturities and redemptions of long-term debt, including the maturity of Ameren (parent)’s $425 million senior unsecured notes. These financing activities, along with cash provided by operating activities where used to fund investing activities and pay dividends.

No cash from financing activities was used for discontinued operations during 2015.

Ameren Missouri’s financing activities used net cash of $325 million in 2015, compared with $113 million in 2014. During 2015, Ameren Missouri received proceeds of $249 million from a long-term debt issuance, repaid a net $97 million of short-term debt, repaid at maturity $114 million of long-term debt, and received a $224 million contribution from Ameren (parent). In comparison, during 2014, Ameren Missouri received proceeds of $350 million from a long-term debt issuance and a net $97 million of short-term debt, repaid at maturity $104 million of long-term debt, and repaid $105 million to the money pool. In both years, these financing activities, along with cash provided by operating activities where used to fund investment activities and pay dividends.

Ameren Illinois' financing activities provided net cash of $220 million in 2015, compared with $383 million in 2014. During 2015, Ameren Illinois received proceeds of $248 million from a long-term debt issuance, repaid a net $32 million of short-term debt, and repaid $15 million to the money pool. In comparison, during 2014, Ameren Illinois received proceeds of $548 million from two long-term debt issuances and a net $32 million of short-term debt, repaid existing long-term debt of $163 million, and repaid $41 million to the money pool. In both years, these financing activities, along with cash provided by operating activities where used to fund investment activities.

2014 versus 2013

Ameren's financing activities associated with continuing operations provided net cash of $141 million in 2014, compared with 2013 when Ameren used cash of $149 million. During 2014, Ameren and its registrant subsidiaries issued long-term and short-term debt to fund the maturities and redemptions of long-term debt, including the maturity of Ameren (parent)’s $425 million senior unsecured notes. In 2014, Ameren used cash from these financing activities, along with cash provided by operating activities to fund investing activities and pay dividends. In comparison, during 2013, Ameren and its registrant subsidiaries issued long-term and short-term debt to fund the maturities and redemptions of long-debt and to fund the $235 million that Ameren was required to leave with New AER upon its divestiture in December 2013, pursuant to the transaction agreement with

IPH. In 2013, Ameren used cash on hand, cash from the issuances of debt, along with cash provided by operating activities to fund investing activities and pay dividends.

No cash from financing activities was used for discontinued operations during 2014.

Ameren Missouri’s financing activities used net cash of $113 million in 2014, compared with $603 million in 2013. During 2014, Ameren Missouri received proceeds of $350 million from a long-term debt issuance and a net $97 million from short-term debt, repaid at maturity $104 million of long-term debt, repaid $105 million to the money pool. In comparison, during 2013, Ameren Missouri repaid $244 million of long-term debt, and received $105 million from the money pool. In both years, including cash on hand during 2013, these financing activities, along with cash provided by operating activities were used to fund investment activities and pay dividends.

Ameren Illinois' financing activities provided net cash of $383 million in 2014, compared with $45 million in 2013. During 2014, Ameren Illinois received proceeds of $548 million from two long-term debt issuances and a net $32 million from short-term debt, repaid existing long-term debt of $163 million, and repaid $41 million to the money pool. In comparison, during 2013, Ameren Illinois received proceeds of $278 million from a long-term debt issuance, repaid at maturity $150 million of long-term debt, and paid dividends. In both years, these financing activities, along with cash provided by operating activities were used to fund investment activities.

Credit Facility Borrowings and Liquidity

The liquidity needs of Ameren, Ameren Missouri, and Ameren Illinois are typically supported through the use of available cash, short-term intercompany borrowings, drawings under committed bank credit agreements, or commercial paper issuances. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report for additional information on credit agreements, short-term borrowing activity, commercial paper issuances, relevant interest rates, and borrowings under Ameren’s money pool arrangements.

The following table presents Ameren's consolidated liquidity as of December 31, 2015:

		Available at December 31, 2015
Ameren and Ameren Missouri:
Missouri Credit Agreement – borrowing capacity		$	1,000
Less: Ameren (parent) commercial paper outstanding		176
Missouri Credit Agreement – credit available		824
Ameren and Ameren Illinois:
Illinois Credit Agreement – borrowing capacity		1,100
Less: Ameren (parent) commercial paper outstanding		125
Less: Letters of credit		13
Illinois Credit Agreement – credit available		962
Total Credit Available		$	1,786
Cash and cash equivalents		292
Total Liquidity		$	2,078

Borrowings by Ameren under either of the Credit Agreements are due and payable no later than the maturity date, while borrowings by Ameren Missouri and Ameren Illinois are due and payable no later than the earlier of the maturity date or 364 days after the date of such borrowing (subject to the right of each borrower to re-borrow in accordance with the terms of the applicable Credit Agreement). The Credit Agreements are currently scheduled to mature in December 2019, but the maturity date may be extended once or twice for additional one year periods upon mutual consent of the borrowers and lenders. The Credit Agreements are used to borrow cash, to issue letters of credit, and to support issuances under Ameren’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper programs. Either of the Credit Agreements are available to Ameren to support issuances under Ameren’s commercial paper program, subject to borrowing sublimits. The Missouri Credit Agreement is available to support issuances under Ameren Missouri’s commercial paper program. The Illinois Credit Agreement is available to support issuances under Ameren Illinois’ commercial paper program. During 2015, borrowings under the Ameren, Ameren Missouri, and Ameren Illinois commercial paper programs were available at lower interest rates than the interest rates of borrowings under the Credit Agreements. As such, commercial paper issuances were a preferred source of third-party short-term debt relative to credit facility borrowings.

The following table presents the maximum aggregate amount available to each borrower under each facility:

	Missouri Credit Agreement				Illinois Credit Agreement
Ameren	$	700			$	500
Ameren Missouri	800				(a)
Ameren Illinois	(a)				800

(a)	Not applicable.

Subject to applicable regulatory short-term borrowing authorizations, these credit arrangements are also available to Ameren's other subsidiaries through direct short-term borrowings from Ameren, including, but not limited to, Ameren Services, through a money pool agreement. Ameren has money pool agreements with and among its subsidiaries to coordinate and to provide for certain short-term cash and working capital requirements. Ameren Missouri and Ameren Illinois borrow from the utility money pool when funds are available before utilizing the Credit Agreements and commercial paper programs because the utility money pool interest rates are typically lower. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report for a detailed explanation of the money pool arrangements.

The issuance of short-term debt securities by Ameren's utility subsidiaries is subject to approval by the FERC under the Federal Power Act. In January 2016, Ameren Missouri requested an extension of its existing FERC authorization to issue up to $1 billion of short-term debt securities through March 2018. Ameren Missouri expects FERC approval of that authorization in March 2016. In September 2014, the FERC issued an order authorizing Ameren Illinois to issue up to $1 billion of short-term debt securities through September 15, 2016. In July 2015, the FERC

issued an order authorizing ATXI to issue up to $300 million of short-term debt securities through July 14, 2017.

The Ameren Companies continually evaluate the adequacy and appropriateness of their liquidity arrangements for changing business conditions. When business conditions warrant, changes may be made to existing credit agreements or to other short-term borrowing arrangements.

Long-term Debt and Equity

The following table presents the issuances (net of issuance discounts), redemptions, repurchases, and maturities of long-term debt for the years ended December 31, 2015, 2014, and 2013 for the Ameren Companies. The Ameren Companies did not issue any common stock or redeem or repurchase any preferred stock during the years ended 2015, 2014, and 2013. In 2015 and 2014, Ameren Missouri received cash capital contributions of $224 million and $215 million, respectively, from Ameren (parent). For additional information related to the terms and uses of these issuances and effective registration statements, see Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report.

	Month Issued, Redeemed, Repurchased, or Matured		2015				2014				2013
Issuances
Ameren (parent)
2.70% Senior unsecured notes due 2020	November		$	350			$	—			$	—
3.65% Senior unsecured notes due 2026	November		350				—				—
Ameren Missouri:
3.50% Senior secured notes due 2024	April		—				350				—
3.65% Senior secured notes due 2045	April		249				—				—
Ameren Illinois:
4.80% Senior secured notes due 2043	December		—				—				278
4.30% Senior secured notes due 2044	June		—				248				—
3.25% Senior secured notes due 2025	December		—				300				—
4.15% Senior secured notes due 2046	December		248				—				—
Total long-term debt issuances			$	1,197			$	898			$	278
Redemptions, Repurchases, and Maturities
Ameren (Parent):
8.875% Senior unsecured notes due 2014	May		$	—			$	425			$	—
Ameren Missouri:
City of Bowling Green capital lease (Peno Creek CT)	December		6				5				5
1993 5.45% Series pollution control revenue bonds due 2028	October		—				—				44
4.65% Senior secured notes due 2013	October		—				—				200
5.50% Senior secured notes due 2014	May		—				104				—
4.75% Senior secured notes due 2015	April		114				—				—
Ameren Illinois:
8.875% Senior secured notes due 2013	December		—				—				150
5.90% Series 1993 due 2023(a)	January		—				32				—
5.70% 1994A Series due 2024(a)	January		—				36				—
5.95% 1993 Series C-1 due 2026	January		—				35				—
5.70% 1993 Series C-2 due 2026	January		—				8				—
5.40% 1998A Series due 2028	January		—				19				—
5.40% 1998B Series due 2028	January		—				33				—
Total long-term debt redemptions, repurchases, and maturities			$	120			$	697			$	399

(a) Less than $1 million principal amount of the bonds remain outstanding after redemption.

In February 2016, Ameren Missouri's 5.40% senior secured notes matured and were repaid using available cash and commercial paper borrowings.

In June 2015, Ameren, Ameren Missouri, and Ameren Illinois filed a Form S-3 shelf registration statement registering the issuance of an indeterminate amount of certain types of securities. The registration statement became effective immediately upon filing. It will expire in June 2018.

The Ameren Companies may sell securities registered under their effective registration statements if market conditions and capital requirements warrant such sales. Any offer and sale will be made only by means of a prospectus that meets the requirements of the Securities Act of 1933 and the rules and regulations thereunder.

Indebtedness Provisions and Other Covenants

At December 31, 2015, the Ameren Companies were in compliance with the provisions and covenants contained within their credit agreements, indentures, and articles of incorporation. See Note 4 – Short-term Debt and Liquidity and Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for a discussion of covenants and provisions (and applicable cross-default provisions) contained in our credit agreements and in certain of the Ameren Companies’ indentures and articles of incorporation.

We consider access to short-term and long-term capital markets to be a significant source of funding for capital requirements not satisfied by cash generated from our operating activities. Inability to raise capital on reasonable terms, particularly during times of uncertainty in the capital markets, could negatively affect our ability to maintain and expand our businesses. After assessing its current operating performance, liquidity, and credit ratings (see Credit Ratings below), Ameren, Ameren Missouri, and Ameren Illinois each believes that it will continue to have access to the capital markets. However, events beyond Ameren's, Ameren Missouri's, and Ameren Illinois' control may create uncertainty in the capital markets or make access to the capital markets uncertain or limited. Such events could increase our cost of capital and adversely affect our ability to access the capital markets.

Dividends and Return of Capital

Ameren paid to its shareholders common stock dividends totaling $402 million, or $1.655 per share, in 2015, $390 million, or $1.61 per share, in 2014, and $388 million, or $1.60 per share, in 2013.

The amount and timing of dividends payable on Ameren’s common stock are within the sole discretion of Ameren’s board of directors. Ameren's board of directors has not set specific targets or payout parameters when declaring common stock dividends, but it considers various factors, including Ameren’s overall payout ratio, payout ratios of our peers, projected cash flow and potential future cash flow requirements, historical earnings and cash flow, projected earnings, impacts of regulatory orders or legislation, and other key business considerations. Ameren expects its dividend payout ratio to be between 55% and 70% of earnings over the next few years. On February 12, 2016, the board of directors of Ameren declared a quarterly dividend on Ameren’s common stock of 42.5 cents per share, payable on March 31, 2016, to shareholders of record on March 9, 2016.

Certain of our financial agreements and corporate organizational documents contain covenants and conditions that, among other things, restrict the Ameren Companies’ payment of dividends in certain circumstances.

Ameren Illinois’ articles of incorporation require its dividend

payments on common stock to be based on ratios of common stock to total capitalization and other provisions related to certain operating expenses and accumulations of earned surplus. Additionally, Ameren has committed to the FERC to maintain a minimum of 30% equity in its capital structure at Ameren Illinois.

Ameren Missouri and Ameren Illinois, as well as certain other nonregistrant Ameren subsidiaries, are subject to Section 305(a) of the Federal Power Act, which makes it unlawful for any officer or director of a public utility, as defined in the Federal Power Act, to participate in the making or paying of any dividend from any funds “properly included in capital account.” The FERC has consistently interpreted the provision to allow dividends to be paid as long as (1) the source of the dividends is clearly disclosed, (2) the dividends are not excessive, and (3) there is no self-dealing on the part of corporate officials. At a minimum, Ameren believes that dividends can be paid by its subsidiaries that are public utilities from net income and from retained earnings. In addition, under Illinois law, Ameren Illinois may not pay any dividend on its stock unless, among other things, its earnings and earned surplus are sufficient to declare and pay a dividend after provision is made for reasonable and proper reserves, or unless Ameren Illinois has specific authorization from the ICC.

At December 31, 2015, the amount of restricted net assets of wholly owned subsidiaries of Ameren that may not be distributed to Ameren in the form of a loan or dividend was $2.3 billion.

The following table presents common stock dividends paid by Ameren Corporation to its common shareholders and by Ameren Missouri and Ameren Illinois to their parent, Ameren:

	2015				2014				2013
Ameren Missouri	$	575			$	340		(a)	$	460
Ameren Illinois	—				—				110
Ameren	402				390				388

(a)	Additionally, during 2014, Ameren Missouri returned capital of $215 million to Ameren (parent).

Ameren Missouri and Ameren Illinois each have issued preferred stock, which provides for cumulative preferred stock dividends. Each company’s board of directors considers the declaration of the preferred stock dividends to shareholders of record on a certain date, stating the date on which the dividend is payable and the amount to be paid. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for further detail concerning the preferred stock issuances.

Contractual Obligations

The following table presents our contractual obligations as of December 31, 2015. See Note 11 – Retirement Benefits under Part II, Item 8, of this report for information regarding expected minimum funding levels for our pension plans. These expected pension funding amounts are not included in the table below. In addition, routine short-term purchase order commitments are not included.

	Less than 1 Year				1 – 3 Years				3 – 5 Years				After 5 Years				Total
Ameren:(a)
Long-term debt and capital lease obligations(b)	$	395			$	1,521			$	1,023			$	4,392			$	7,331
Interest payments(c)	362				626				435				2,771				4,194
Operating leases(d)	14				25				23				30				92
Other obligations(e)	1,323				1,676				557				1,128				4,684
Total cash contractual obligations	$	2,094			$	3,848			$	2,038			$	8,321			$	16,301
Ameren Missouri:
Long-term debt and capital lease obligations(b)	$	266			$	814			$	673			$	2,382			$	4,135
Interest payments(c)	211				367				259				1,687				2,524
Operating leases(d)	12				22				21				29				84
Other obligations(e)	833				1,178				325				469				2,805
Total cash contractual obligations	$	1,322			$	2,381			$	1,278			$	4,567			$	9,548
Ameren Illinois:
Long-term debt(b)	$	129			$	707			$	—			$	1,660			$	2,496
Interest payments(c)	129				215				132				1,019				1,495
Operating leases(d)	1				2				2				1				6
Other obligations(e)	452				479				232				659				1,822
Total cash contractual obligations	$	711			$	1,403			$	366			$	3,339			$	5,819

(a)	Includes amounts for registrant and nonregistrant Ameren subsidiaries and intercompany eliminations.

(b)	Excludes unamortized discount and premium and debt issuance costs of $56 million, $25 million, and $25 million at Ameren, Ameren Missouri, and Ameren Illinois, respectively. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8 of this report, for discussion of items included herein.

(c)	The weighted-average variable-rate debt has been calculated using the interest rate as of December 31, 2015.

(d)

Amounts for certain land-related leases have indefinite payment periods. The annual obligation of $3 million, $2 million, and $1 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, for these items is included in the Less than 1 Year, 1 – 3 Years, and 3 – 5 Years columns. See Leases in Note 15 – Commitments and Contingencies under Part II, Item 8 of this report, for discussion of items included herein.

(e)	See Other Obligations in Note 15 – Commitments and Contingencies under Part II, Item 8 of this report, for discussion of items included herein.

As of December 31, 2015, Ameren, Ameren Missouri, and Ameren Illinois had no unrecognized tax benefits (detriments) for uncertain tax positions.

Off-Balance-Sheet Arrangements

At December 31, 2015, none of the Ameren Companies had off-balance-sheet financing arrangements, other than operating leases entered into in the ordinary course of business, letters of credit, and Ameren parent guarantee arrangements on behalf of its subsidiaries. None of the Ameren Companies expect to engage in any significant off-balance-sheet financing arrangements in the near future.

Credit Ratings

Our credit ratings affect our liquidity, our access to the capital markets and credit markets, our cost of borrowing under our credit facilities, our commercial paper programs, and our collateral posting requirements under commodity contracts.

The following table presents the principal credit ratings of the Ameren Companies by Moody’s and S&P effective on the date of this report:

	Moody’s	S&P
Ameren:
Issuer/corporate credit rating	Baa1	BBB+
Senior unsecured debt	Baa1	BBB
Commercial paper	P-2	A-2
Ameren Missouri:
Issuer/corporate credit rating	Baa1	BBB+
Secured debt	A2	A
Senior unsecured debt	Baa1	BBB+
Commercial paper	P-2	A-2
Ameren Illinois:
Issuer/corporate credit rating	A3	BBB+
Secured debt	A1	A
Senior unsecured debt	A3	BBB+
Commercial paper	P-2	A-2

The cost of borrowing under our credit facilities can also fluctuate depending upon the credit ratings of the borrower. A credit rating is not a recommendation to buy, sell, or hold securities. It should be evaluated independently of any other rating. Ratings are subject to revision or withdrawal at any time by the rating organization.

Collateral Postings

Any adverse change in our credit ratings may reduce access to capital and trigger additional collateral postings and prepayments. Such changes may also increase the cost of borrowing, resulting in an adverse effect on earnings. Cash collateral postings and prepayments made with external parties, including postings related to exchange-traded contracts, and cash collateral posted by external parties were immaterial at Ameren, Ameren Missouri, and Ameren Illinois at December 31, 2015. Sub-investment-grade issuer or senior unsecured debt rating (lower than “BBB-” or “Baa3”) at December 31, 2015, could have resulted in Ameren, Ameren Missouri, or Ameren Illinois being required to post additional collateral or other assurances for certain trade obligations amounting to $143 million, $72 million, and $71 million, respectively.

Changes in commodity prices could trigger additional collateral postings and prepayments. Based on credit ratings at December 31, 2015, if market prices were 15% higher or lower than December 31, 2015 levels in the next 12 months and 20% higher or lower thereafter through the end of the term of the commodity contracts, then Ameren, Ameren Missouri, or Ameren Illinois would only be required to post an immaterial amount of collateral or other assurances for certain trade obligations.

OUTLOOK

We seek to earn competitive returns on investments in our businesses. We are seeking to improve our regulatory frameworks and cost recovery mechanisms and simultaneously pursuing constructive regulatory outcomes within existing frameworks. We are seeking to align our overall spending, both operating and capital, with economic conditions and with regulatory frameworks established by our regulators. Consequently, we are focused on minimizing the gap between allowed and earned returns on equity. We intend to allocate capital resources to our business opportunities that we expect to offer the most attractive risk-adjusted return potential.

Below are some key trends, events, and uncertainties that are reasonably likely to affect our results of operations, financial condition, or liquidity, as well as our ability to achieve strategic and financial objectives, for 2016 and beyond.

Operations

•	Our strategy for earning competitive returns on our investments involves meeting customer energy needs in an efficient fashion, working to enhance regulatory frameworks, making timely and well-supported rate case filings, and aligning overall spending with those rate case outcomes, economic conditions, and return opportunities.

•

Ameren continues to pursue its plans to invest in FERC-regulated electric transmission. MISO has approved three electric transmission projects to be developed by ATXI. The first project, Illinois Rivers, involves the construction of a transmission line from western Indiana across the state of Illinois to eastern Missouri. The last section of this project is expected to be completed by 2019. The Spoon River project

in northwest Illinois and the Mark Twain project in northeast Missouri are the other two MISO-approved projects to be constructed by ATXI. These two projects are expected to be completed in 2018. The Illinois Rivers and the Spoon River projects have received all of the necessary commission approvals to authorize their construction while ATXI is still seeking approval from the MoPSC for the Mark Twain project. The total investment in all three projects is expected to be more than $1.0 billion from 2016 through 2019. This total includes over $60 million of investment by Ameren Illinois to construct connections to its existing transmission system. In addition to its investment in the MISO-approved projects, Ameren Illinois expects to invest $1.9 billion in electric transmission assets from 2016 through 2020 to address load growth and reliability requirements.

•

Both Ameren Illinois and ATXI use a forward-looking rate calculation with an annual revenue requirement reconciliation for each company’s electric transmission business. With the rates that became effective on January 1, 2016, and the currently allowed 12.38% return on equity, the 2016 revenue requirement for Ameren Illinois’ electric transmission business would be $241 million, which represents a $42 million increase over the 2015 revenue requirement due to rate base growth. These rates reflect a capital structure composed of 51.9% common equity and a projected rate base of $1.2 billion. With the rates that became effective on January 1, 2016, and the currently allowed 12.38% return on equity, the 2016 revenue requirement for ATXI’s electric transmission business would be $140 million, which represents a $60 million increase over the 2015 revenue requirement due to rate base growth, primarily as a result of the Illinois Rivers project. These rates reflect a capital structure composed of 56.1% common equity and a projected rate base of $0.9 billion.

•

The 12.38% return on common equity is the subject of two FERC complaint proceedings, the November 2013 complaint case and the February 2015 complaint case, that challenge the allowed base return on common equity for MISO transmission owners. In December 2015, a FERC administrative law judge issued an initial decision in the November 2013 complaint case that would lower the allowed base return on common equity to 10.32%. The FERC is expected to issue a final order on the November 2013 complaint case by October 2016. An initial decision from an administrative law judge in the February 2015 complaint case is expected to be issued by June 30, 2016, which will subsequently require FERC approval. A 50 basis point reduction in the FERC-allowed base return on common equity would reduce Ameren's and Ameren Illinois' annual earnings by an estimated $6 million and $3 million, respectively, based on each company’s 2016 projected rate base. Ameren and Ameren Illinois recorded current regulatory liabilities on their respective balance sheets as of December 31, 2015, representing their estimate of the potential refunds from the November 2013 refund effective date through December 2015.

•	In January, 2015, a FERC-approved incentive adder of up to 50 basis points on the allowed base return on common

equity for our participation in an RTO became effective. Upon the issuance of the final order addressing the November 2013 complaint case, beginning with its January 2015 effective date, the incentive adder will reduce any refund to customers relating to a reduction of the base return on common equity.

•

In April 2015, the MoPSC issued an order approving a $122 million increase in Ameren Missouri’s annual revenues for electric service, including $109 million related to the increase in net energy costs above those included in base rates previously authorized by the MoPSC. The revenue increase was based on a 9.53% return on common equity, a capital structure composed of 51.8% common equity, and a rate base of $7.0 billion to reflect investments through December 31, 2014. Rate changes consistent with the order became effective on May 30, 2015. Ameren Missouri’s revenue requirement, prior to May 30, 2015, was based on a 9.8% return on common equity, a capital structure composed of 52.3% common equity, and a rate base of $6.8 billion. Accordingly, the level of earnings reflected in the revenue requirement in effect after May 30, 2015, is lower than the level of earnings reflected in the previously effective revenue requirement. The order approved Ameren Missouri’s request for continued use of the FAC; however, it changed the FAC to exclude all transmission revenues and substantially all transmission charges. The order did not approve the continued use of regulatory tracking mechanisms for storm costs or for vegetation management and infrastructure inspection costs. These changes to Ameren Missouri’s recovery mechanisms are expected to contribute to regulatory lag. For example, the April 2015 MoPSC electric rate order included $29 million of transmission charges in base rates that were previously included in the FAC. Ameren Missouri expects transmission charges to increase to $53 million in 2016, with further cost increases expected in the foreseeable future. However, transmission revenues included in base rates in the April 2015 MoPSC electric rate order totaled $34 million and are expected to remain relatively constant in 2016 and into the near future.

•

Ameren Missouri supplies electricity to Noranda’s aluminum smelter located in southeast Missouri. In its April 2015 electric rate order, the MoPSC approved a rate design that established $78 million in annual revenues, net of fuel and purchased power costs, as Noranda’s portion of Ameren Missouri’s revenue requirement. The portion of Ameren Missouri’s annual revenue requirement reflected in Noranda’s electric rate is based on the smelter using approximately 4.2 million megawatthours annually, which is almost 100% of its operating capacity. In January 2016, Noranda announced that production had been idled at two of its three pot lines following an electric supply circuit failure and that the third pot line, which was not directly affected by the circuit failure, will be curtailed on or before March 12, 2016, unless Noranda "is able to secure a substantially more sustainable power rate." On February 8, 2016, Noranda filed voluntary petitions for a court-supervised restructuring process under Chapter 11 of the United States Bankruptcy Code. In the filing, Noranda reaffirmed that the

remaining pot line will continue to operate at the smelter until March 2016, at which time operation of the line will be curtailed. Noranda stated it would maintain the flexibility to restart operations at the smelter should conditions allow. As a result of these events in 2016, actual sales volumes to Noranda will be significantly below the sales volumes reflected in rates and therefore, Ameren Missouri will not fully recover its revenue requirement until rates are adjusted by the MoPSC in a future electric rate case to reflect Noranda’s actual sales volumes. Ameren Missouri estimates a $32 million reduction in 2016 earnings, compared to 2015, relating to the significantly lower expected electric sales volumes to Noranda after consideration of the FAC provision that allows Ameren Missouri to retain a portion of its off-system sales. In January 2016, Ameren Missouri filed a notice with the MoPSC that would enable Ameren Missouri to file an electric rate case after 60 days. Ameren Missouri expects to file an electric rate case in 2016 and expects the resulting new rates to reflect Noranda's actual sales volumes which would prospectively eliminate the impact of the current revenue shortfall. Rate case proceedings take place over a period of up to 11 months from the date of filing. Ameren Missouri will continue to monitor Noranda’s sales volumes and to evaluate its regulatory and legislative options that might mitigate adverse financial impacts.

•

From 2013 through 2015, Ameren Missouri invested $134 million in customer energy efficiency programs and realized $174 million of net shared benefits under the MEEIA plan approved in August 2012. Additionally, the plan established a performance incentive that would provide Ameren Missouri an opportunity to earn additional revenues based on its achievement of certain customer energy efficiency goals, including $19 million if 100% of the goals were achieved during the three-year period, with the potential to earn more if Ameren Missouri’s energy savings exceeded those goals. In June 2015, the MoPSC staff filed a complaint case with the MoPSC regarding the method and inputs used in calculating the performance incentive for 2014 and 2015. In November 2015, the MoPSC issued an order that adopted the MoPSC staff’s method and inputs used in calculating the performance incentive for 2014 and 2015. Ameren Missouri has filed an appeal of the order with the Missouri Court of Appeals, Western District. If the Missouri Court of Appeals upholds the MoPSC order, the performance incentive awarded from the 2014 and 2015 MEEIA programs will be significantly less than the performance incentive calculated using Ameren Missouri’s interpretation. Ameren Missouri has not recorded revenues associated with the performance incentive for any of the MEEIA program years. Ameren Missouri believes it will ultimately be found to have exceeded 100% of the customer energy efficiency goals, and it therefore expects to recognize revenues of at least $19 million in 2016.

•	Net shared benefits compensated Ameren Missouri for the current year and longer-term financial impacts of customer energy efficiency programs in each year of the program from 2013 through 2015. The March 2016 through February 2019 MEEIA plan is designed differently. The throughput disincentive included in the March 2016 through February

2019 MEEIA plan is designed to make Ameren Missouri earnings neutral each year for its customer energy efficiency investments, including the lost sales volume that occur in that year, and does not compensate for the longer-term financial impacts of customer energy efficiency programs until those sales volumes are lost in a future year. The unfavorable effects of sales volume reductions in 2016 from the 2013 through 2015 energy efficiency programs were previously recognized during those years as net shared benefits and, therefore, any such lost sales volumes will negatively impact 2016 earnings.

•

In February 2016, the MoPSC issued an order approving Ameren Missouri's March 2016 to February 2019 MEEIA plan which included a portfolio of customer energy efficiency programs along with a rider to collect the program costs, the throughput disincentive, and a performance incentive from customers. The throughput disincentive recovery will replace the net shared benefits that were collected under the 2013 through 2015 MEEIA plan. The MEEIA rider will allow Ameren Missouri to collect the throughput disincentive without a traditional rate proceeding until such time as lower volumes resulting from the MEEIA programs are reflected in base rates. Customer rates will be based upon both forecasted program costs and throughput disincentive which will be annually reconciled to actual results. Beginning in March 2016, Ameren Missouri intends to invest $158 million over the three-year period in customer energy efficiency programs. In addition, similar to the MEEIA plan that ended in December 2015, the MoPSC's order approved a performance incentive that would provide Ameren Missouri an opportunity to earn additional revenues by achieving certain customer energy efficiency goals, including $27 million if 100% of the goals are achieved during the three-year period, with the potential to earn more if Ameren Missouri's energy savings exceed those goals. Ameren Missouri must achieve at least 25% of its energy efficiency goals before it earns a performance incentive.

•

The IEIMA provides for an annual reconciliation of the revenue requirement necessary to reflect the actual costs incurred in a given year with the revenue requirement that was reflected in customer rates for that year. Consequently, Ameren Illinois' 2016 electric delivery service revenues will be based on its 2016 actual recoverable costs, rate base, and return on common equity as calculated under the IEIMA's performance-based formula ratemaking framework. The 2016 revenue requirement is expected to be higher than the 2015 revenue requirement, because of an expected increase in recoverable costs, rate base growth, and an expected increase in the monthly average yield of United States Treasury bonds. A 50 basis point change in the average monthly yields of the 30-year United States Treasury bonds would result in an estimated $6 million change in Ameren's and Ameren Illinois' net income, based on its 2016 projected rate base.

•	In December 2015, the ICC issued an order with respect to Ameren Illinois’ annual update filing. The ICC approved a $106 million increase in Ameren Illinois’ electric delivery service revenue requirement beginning in January 2016. These rates have affected and will continue to affect Ameren

Illinois' cash receipts during 2016, but will not be the sole determinant of its electric delivery service operating revenues, which will instead be largely determined by the IEIMA's 2016 revenue requirement reconciliation. The 2016 revenue requirement reconciliation, as discussed above, is expected to result in a regulatory asset that will be collected from customers in 2018.

•

In December 2015, the ICC issued a rate order that approved an increase in revenues for Ameren Illinois' natural gas delivery service of $45 million. The revenue increase was based on a 9.6% return on common equity, a capital structure composed of 50% common equity, and a rate base of $1.2 billion. The rate order was based on a 2016 future test year. The rate changes were in effect in January 2016. In addition, the rate order approved the VBA for residential and small nonresidential customers beginning in 2016.

•

Ameren Missouri's next scheduled refueling and maintenance outage at its Callaway energy center will be in the spring of 2016 and Ameren Missouri expects to incur $37 million of maintenance expenses in 2016. There was no refueling outage scheduled in 2015; however, $9 million in preparation costs were incurred in 2015 for the 2016 scheduled outage. During the 2014 refueling, Ameren Missouri incurred maintenance expenses of $36 million. During a scheduled outage, which occurs every 18 months, maintenance expenses increase relative to non-outage years. Additionally, depending on the availability of its other generation sources and the market prices for power, Ameren Missouri's purchased power costs may increase and the amount of excess power available for sale may decrease versus non-outage years. Changes in purchased power costs and excess power available for sale are included in the FAC, which results in limited impacts to earnings.

•

Ameren Missouri was engaged in litigation with an insurer to recover an unpaid liability insurance claim for the December 2005 breach of the upper reservoir at Ameren Missouri's Taum Sauk pumped-storage hydroelectric energy center. As of December 31, 2015, Ameren Missouri had an insurance receivable of $41 million. In February 2016, Ameren Missouri and the insurer reached a settlement that resulted in Ameren Missouri receiving $42 million in February 2016.

•

As we continue to experience cost increases and to make infrastructure investments, Ameren Missouri and Ameren Illinois expect to seek regular electric and natural gas rate increases and timely cost recovery and tracking mechanisms from their regulators. Ameren Missouri and Ameren Illinois will also seek, as necessary, legislative solutions to address regulatory lag and to support investment in their utility infrastructure for the benefit of their customers, including Ameren Missouri's current efforts to advocate for a legislative solution to support Noranda's operations. These pressures include limited economic growth in their service territories, customer conservation efforts, the impacts of additional customer energy efficiency programs, increased customer use of innovative and increasingly cost-effective technological advances including distributed generation and storage, increased investments and expected future investments for environmental compliance, system reliability improvements, and new

generation capacity, including renewable energy requirements. Increased investments also result in higher depreciation and financing costs. Increased costs are also expected from rising employee benefit costs and higher property and income taxes, among other costs.

For additional information regarding recent rate orders and related appeals, Noranda, Ameren Missouri's MEEIA plans, FERC return on equity complaint cases, and other pending requests filed with state and federal regulatory commissions, see Note 2 – Rate and Regulatory Matters, and Note 10 – Callaway Energy Center, under Part II, Item 8, of this report.

Liquidity and Capital Resources

•

We expect to incur significant capital expenditures in order to make investments to improve our electric and natural gas utility infrastructure and to comply with existing environmental regulations. We estimate that we will incur up to $11.5 billion (Ameren Missouri – up to $4.3 billion; Ameren Illinois – up to $6.2 billion; ATXI – up to $1.0 billion) of capital expenditures during the period from 2016 through 2020, excluding the impact of the Clean Power Plan.

•

Environmental regulations, including those related to CO2 emissions, or other actions taken by the EPA could result in significant increases in capital expenditures and operating costs. These costs could be prohibitive at some of Ameren Missouri's coal-fired energy centers. Ameren Missouri's capital expenditures are subject to MoPSC prudence reviews, which could result in cost disallowances as well as regulatory lag. The cost of Ameren Illinois’ purchased power and gas purchased for resale could increase. However, Ameren Illinois expects these costs would be recovered from customers with no material adverse effect on its results of operations, financial position, or liquidity. Ameren's and Ameren Missouri's earnings could benefit from increased investment to comply with environmental regulations if those investments are reflected and recovered on a timely basis in rates charged to customers.

•

Ameren is evaluating the Clean Power Plan's potential impacts to its operations, including those related to electric system reliability, and its level of investment in customer energy efficiency programs, renewable energy, and other forms of generation investment. In February 2016, the United States Supreme Court stayed the Clean Power Plan and all implementation requirements until such time as legal appeals are concluded. Appeals are not expected to conclude prior to 2018. If the rule is ultimately upheld and implemented in substantially similar form to the rule when issued, Ameren Missouri expects to incur increased net fuel and operating costs, and make new or accelerated capital expenditures, in addition to the costs of making modifications to existing operations in order to achieve compliance. Compliance measures could result in the closure or alteration of the operation of some of Ameren Missouri’s coal and natural-gas-fired energy centers, which could result in increased operating costs.

•	Ameren Missouri files a nonbinding integrated resource plan with the MoPSC every three years. Ameren Missouri’s

integrated resource plan filed with the MoPSC in October 2014, prior to the issuance of the Clean Power Plan, was a 20-year plan that supported a more fuel-diverse energy portfolio in Missouri, including coal, solar, wind, natural gas, and nuclear power. The plan involves expanding renewable generation, retiring coal-fired generation as energy centers reach the end of their useful lives, continuation and expansion of the then-existing energy efficiency programs, and adding natural-gas-fired combined cycle generation.

•

The Ameren Companies have multiyear credit agreements that cumulatively provide $2.1 billion of credit through December 2019, subject to a 364-day repayment term in the case of Ameren Missouri and Ameren Illinois. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report for additional information regarding the Credit Agreements. Ameren, Ameren Missouri, and Ameren Illinois believe that their liquidity is adequate given their expected operating cash flows, capital expenditures, and related financing plans. However, there can be no assurance that significant changes in economic conditions, disruptions in the capital and credit markets, or other unforeseen events will not materially affect their ability to execute their expected operating, capital, or financing plans.

•	In November 2015, Ameren (parent) issued $350 million of 2.70% senior unsecured notes due November 15, 2020 and $350 million of 3.65% senior unsecured notes due February 15, 2026. Ameren used the proceeds to pay a portion of short-term debt consisting of commercial paper issuances. Ameren expects to incur interest charges of $22 million annually related to these issuances.

•

In December 2015, a federal tax law was enacted that authorized the continued use of bonus depreciation that allows for an acceleration of deductions for tax purposes at a rate of 50% for 2015, 2016, and 2017. The rate will be reduced to 40% in 2018 and then to 30% in 2019. Bonus depreciation will be phased out in 2020 unless a new law is enacted. Bonus depreciation is expected to increase cash flow through at least 2020. Ameren expects to use this incremental cash flow to make capital investments in utility infrastructure for the benefit of its customers. Without these investments, bonus depreciation would reduce rate base, which reduces our revenue requirements and future earnings growth. The impact of bonus depreciation on Ameren Missouri, Ameren Illinois, and ATXI will vary based on investment levels at each company.

•

As of December 31, 2015, Ameren had $453 million in tax benefits from federal and state net operating loss carryforwards (Ameren Missouri – $39 million and Ameren Illinois – $131 million) and $144 million in federal and state income tax credit carryforwards (Ameren Missouri – $26 million and Ameren Illinois – $2 million). In addition, Ameren has $37 million of expected state income tax refunds and state overpayments. Consistent with the tax allocation agreement between Ameren and its subsidiaries, these carryforwards are expected to partially offset income tax liabilities for Ameren Missouri until 2019 and Ameren Illinois until 2021. Ameren does not expect to make material federal income tax payments until 2021. These tax benefits, primarily at the Ameren (parent) level, when realized, would

be available to fund ATXI transmission investments.

•	Ameren expects its cash used for capital expenditures and dividends to exceed cash provided by operating activities over the next several years. Ameren expects to use debt to fund such cash shortfalls; it does not currently expect to issue equity over the next several years.

•	In October 2015, Ameren’s board of directors declared a fourth quarter dividend of 42.5 cents per common share, a 3.7% increase from the prior quarterly dividend rate of 41 cents per share, resulting in an annualized equivalent dividend rate of $1.70 per share.

•

The use of cash from operating activities and from short-term borrowings to fund capital expenditures and other long-term investments may periodically result in a working capital deficit, defined by current liabilities exceeding current assets, as was the case at December 31, 2015, for Ameren. The working capital deficit as of December 31, 2015, was primarily the result of current maturities of long-term debt and commercial paper issuances. The Ameren Companies had $301 million of commercial paper issuances outstanding as of December 31, 2015. With the Credit Agreements and cash and cash equivalents available, the Ameren Companies had access to $1.8 billion of credit capacity available, and $2.1 billion of liquidity at December 31, 2015.

•	In February 2016, $260 million principal amount of Ameren Missouri's 5.40% senior secured notes matured and were repaid using available cash and commercial paper borrowings.

The above items could have a material impact on our results of operations, financial position, or liquidity. Additionally, in the ordinary course of business, we evaluate strategies to enhance our results of operations, financial position, or liquidity. These strategies may include acquisitions, divestitures, and opportunities to reduce costs or increase revenues, and other strategic initiatives to increase Ameren's shareholder value. We are unable to predict which, if any, of these initiatives will be executed. The execution of these initiatives may have a material impact on our future results of operations, financial position, or liquidity.

REGULATORY MATTERS

See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report.

ACCOUNTING MATTERS

Critical Accounting Estimates

Preparation of the financial statements and related disclosures in compliance with GAAP requires the application of appropriate technical accounting rules and guidance, as well as the use of estimates. These estimates involve judgments regarding many factors that in and of themselves could materially affect the financial statements and disclosures. We have outlined below the critical accounting estimates that we believe are the most difficult, subjective, or complex. Any change in the assumptions or judgments applied in determining the following matters, among others, could have a material impact on future financial results.

Accounting Estimate		Uncertainties Affecting Application

Regulatory Mechanisms and Cost Recovery

We defer costs and recognize revenue in accordance with authoritative accounting guidance, and make investments that we assume will be collected in future rates.

•	Regulatory environment and external regulatory decisions and requirements

•	Anticipated future regulatory decisions and our assessment of their impact

•	The impact of prudence reviews, complaint cases, and opposition during the ratemaking process that may limit our ability to timely recover costs and earn a fair return on our investments

•	Ameren Illinois’ assessment of and ability to estimate the current year’s electric delivery service costs to be reflected in revenues and recovered from customers in a subsequent year under the IEIMA performance-based formula ratemaking process

•	Ameren Illinois’ and ATXI's assessment of and ability to estimate the current year’s electric transmission service costs to be reflected in revenues and recovered from customers in a subsequent year under the FERC ratemaking process

•	Ameren Missouri's estimate of revenue recovery under the MEEIA

Basis for Judgment

We determine which costs are recoverable by reviewing previous rulings by regulatory authorities in jurisdictions where we operate and any other factors that may indicate whether cost recovery is probable. If facts and circumstances lead us to conclude that a recorded regulatory asset is no longer probable of recovery or that plant assets are probable of disallowance, we record a charge to earnings, which could be material. Ameren Illinois estimates its annual revenue requirement pursuant to the IEIMA for interim periods by using internal forecasted information, such as projected operations and maintenance expenses, depreciation expense, taxes other than income taxes, and rate base, as well as published forecasted data regarding that year's monthly average yields of the 30-year United States Treasury bonds. Ameren Illinois estimates its annual revenue requirement as of December 31 of each year using that year's actual operating results and assesses the probability of recovery from or refund to customers that the ICC will order at the end of the following year. Variations in costs incurred, investments made, or orders by the ICC or courts can result in a subsequent change in Ameren Illinois' estimate. Ameren Illinois and ATXI follow a similar process for their FERC rate-regulated electric transmission businesses. Ameren Missouri estimates lost revenues resulting from its MEEIA customer energy efficiency programs. Ameren Missouri uses a MEEIA rider to collect from or refund to customers any annual difference in the actual amounts incurred and the amounts collected from customers. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for quantification of these assets or liabilities for each of the Ameren Companies. See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report for a listing of regulatory mechanisms used by Ameren Missouri and Ameren Illinois.

Benefit Plan Accounting

Based on actuarial calculations, we accrue costs of providing future employee benefits in accordance with authoritative accounting guidance regarding benefit plans. See Note 11 – Retirement Benefits under Part II, Item 8, of this report.

•	Future rate of return on pension and other plan assets

•	Valuation inputs and assumptions used in the fair value measurements of plan assets, excluding those inputs that are readily observable

•	Discount rates

•	Health care cost trend rates

•	Timing of employee retirements and mortality assumptions

•	Ability to recover certain benefit plan costs from our customers

•	Changing market conditions that may affect investment and interest rate environments

Basis for Judgment

Our ultimate selection of the discount rate, health care trend rate, and expected rate of return on pension and other postretirement benefit plan assets is based on our consistent application of assumption-setting methodologies and our review of available historical, current, and projected rates, as applicable. We also make mortality assumptions to estimate our pension and other postretirement benefit obligations. See Note 11 – Retirement Benefits under Part II, Item 8, of this report for sensitivity of Ameren’s benefit plans to potential changes in these assumptions.

Accounting for Contingencies

We make judgments and estimates in the recording and the disclosing of liabilities for claims, litigation, environmental remediation, the actions of various regulatory agencies, or other matters that occur in the normal course of business. We record a loss contingency when it is probable that a liability has been incurred and that the amount of the loss can be reasonably estimated.

•	Estimating financial impact of events

•	Estimating likelihood of various potential outcomes

•	Regulatory and political environments and requirements

•	Outcome of legal proceedings, settlements, or other factors

•	Changes in regulation, expected scope of work, technology or timing of environmental remediation

Basis for Judgment

The determination of a loss contingency requires significant judgment as to the expected outcome of the contingency in future periods. In making the determination as to the amount of potential loss and the probability of loss, we consider all available evidence, including the expected outcome of potential litigation. If no estimate is better than another within our range of estimates, we record as our best estimate of a loss the minimum value of our estimated range of outcomes. As additional information becomes available, we reassess the potential liability related to the contingency and revise our estimates. In our evaluation of legal matters, management consults with legal counsel and relies on analysis of relevant case law and legal precedents. See Note 2 – Rate and Regulatory Matters, Note 10 – Callaway Energy Center and Note 15 – Commitments and Contingencies under Part II, Item 8, of this report for information on the Ameren Companies’ contingencies.

Accounting for Income Taxes

Following authoritative accounting guidance, we record the provision for income taxes, deferred tax assets and liabilities, and a valuation allowance against net deferred tax assets, if any. See Note 13 – Income Taxes under Part II, Item 8, of this report.

•	Changes in business, industry, laws, technology, or economic and market conditions affecting forecasted financial condition and/or results of operations

•	Estimates of the amount and character of future taxable income

•	Enacted tax rates applicable to taxable income in years in which temporary differences are recovered or settled

•	Effectiveness of implementing tax planning strategies

•	Changes in income tax laws

•	Results of audits and examinations by taxing authorities

Basis for Judgment

The reporting of tax-related assets and liabilities requires the use of estimates and significant management judgment. Deferred tax assets and liabilities are recorded to represent future effects on income taxes for temporary differences between the basis of assets for financial reporting and tax purposes. Although management believes that current estimates for deferred tax assets and liabilities are reasonable, actual results could differ from these estimates for a variety of reasons, including a change in forecasted financial condition and/or results of operations, change in income tax laws or enacted tax rates, the form, structure, and timing of asset or stock sales or dispositions, and results of audits and examinations by taxing authorities. Valuation allowances against deferred tax assets are recorded when management concludes it is more likely than not such asset will not be realized in future periods. Accounting for income taxes also requires that only tax benefits for positions taken or expected to be taken on tax returns that meet the more-likely-than-not recognition threshold can be recognized or continue to be recognized. Management evaluates each position solely on the technical merits and facts and circumstances of the position, assuming that the position will be examined by a taxing authority that has full knowledge of all relevant information. Significant judgment is required to determine recognition thresholds and the related amount of tax benefits to be recognized. At each period-end, and as new developments occur, management reevaluates its tax positions. See Note 13 – Income Taxes under Part II, Item 8, of this report for the amount of deferred tax assets and uncertain tax positions recorded at December 31, 2015.

Unbilled Revenue

At the end of each period, Ameren, Ameren Missouri, and Ameren Illinois estimate the usage that has been provided to customers but not yet billed. This usage amount, along with a per unit price, is used to estimate an unbilled balance.

•	Estimating customer energy usage

•	Estimating impacts of weather and other usage-affecting factors for the unbilled period

•	Estimating loss of energy during transmission and delivery

Basis for Judgment

We base our estimate of unbilled revenue each period on the volume of energy delivered, as valued by a model of billing cycles and historical usage rates and growth or contraction by customer class for our service area. This figure is then adjusted for the modeled impact of seasonal and weather variations based on historical results. See the balance sheet for each of the Ameren Companies under Part II, Item 8, of this report for unbilled revenue amounts.

Impact of New Accounting Pronouncements

See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report.

EFFECTS OF INFLATION AND CHANGING PRICES

Ameren’s rates for retail electric and natural gas utility service are regulated by the MoPSC and the ICC. Nonretail electric rates are regulated by the FERC. Rate regulation is generally based on the recovery of historical or projected costs. As a result, revenue increases could lag behind changing prices. Ameren Illinois participates in the performance-based formula ratemaking process pursuant to the IEIMA for its electric delivery service business. Ameren Illinois is required to purchase all of its power through procurement processes administered by the IPA. The cost of procured power can be affected by inflation. Within the IEIMA formula, the monthly average yields of 30-year United States Treasury bonds are the basis for Ameren Illinois’ return on equity. Therefore, there is a direct correlation between the yield of United States Treasury bonds, which are affected by inflation, and the earnings of Ameren Illinois’ electric distribution business. Ameren Illinois and ATXI use a company-specific, forward-looking rate formula framework in setting their transmission rates. These forward-looking rates are updated each January with forecasted information. A reconciliation during the year, which adjusts for the actual revenue requirement and actual sales volumes, is used to adjust billing rates in a subsequent year.

The current replacement cost of our utility plant substantially exceeds our recorded historical cost. Under existing regulatory practice, only the historical cost of plant is recoverable from customers. As a result, customer rates designed to provide recovery of historical costs through depreciation might not be

adequate to replace plant in future years.

Ameren Missouri recovers the cost of fuel for electric generation and the cost of purchased power by adjusting rates as allowed through the FAC. The April 2015 MoPSC electric rate order approved Ameren Missouri’s request for continued use of the FAC; however, it changed the FAC to exclude all transmission revenues and substantially all transmission charges. As such, Ameren Missouri is exposed to transmission charges to the extent they exceed transmission revenues. Ameren Illinois recovers power supply costs from electric customers by adjusting rates through a rider mechanism to accommodate changes in power prices.

In our Missouri and Illinois retail natural gas utility jurisdictions, changes in natural gas costs are generally reflected in billings to natural gas customers through PGA clauses.

See Part I, Item 1, and Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information on our cost recovery mechanisms.