Cover and table of contents

Table of Contents Index to Financial Statements

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended June 30, 2026

OR

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

			Commission File Number						Registrant, State of Incorporation, Address and Telephone Number						I.R.S. Employer Identification No.

			1-3526						The Southern Company						58-0690070

(A Delaware Corporation)

30 Ivan Allen Jr. Boulevard, N.W.

Atlanta, Georgia 30308

(404) 506-5000

			1-3164						Alabama Power Company						63-0004250

(An Alabama Corporation)

600 North 18th Street

Birmingham, Alabama 35203

(205) 257-1000

			1-6468						Georgia Power Company						58-0257110

(A Georgia Corporation)

241 Ralph McGill Boulevard, N.E.

Atlanta, Georgia 30308

(404) 506-6526

			001-11229						Mississippi Power Company						64-0205820

(A Mississippi Corporation)

2992 West Beach Boulevard

Gulfport, Mississippi 39501

(228) 864-1211

			001-37803						Southern Power Company						58-2598670

(A Delaware Corporation)

30 Ivan Allen Jr. Boulevard, N.W.

Atlanta, Georgia 30308

(404) 506-5000

			1-14174						Southern Company Gas						58-2210952

(A Georgia Corporation)

725 W. Peachtree Street, N.E.

Atlanta, Georgia 30308

(404) 584-4000

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Securities registered pursuant to Section 12(b) of the Act:

Registrant			Title of Each Class			Trading Symbol(s)			Name of Each Exchange on Which Registered
The Southern Company			Common Stock, par value $0.01 per share			SO			New York Stock Exchange
(NYSE)
The Southern Company			Series 2017B 5.25% Junior Subordinated Notes due 2077			SOJC			NYSE
The Southern Company			Series 2020A 4.95% Junior Subordinated Notes due 2080			SOJD			NYSE
The Southern Company			Series 2020C 4.20% Junior Subordinated Notes due 2060			SOJE			NYSE
The Southern Company			Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081			SO 81			NYSE
The Southern Company			Series 2025A 6.50% Junior Subordinated Notes due 2085			SOJF			NYSE
The Southern Company			2025 Series A Corporate Units			SOMN			NYSE
Georgia Power Company			Series 2017A 5.00% Junior Subordinated Notes due 2077			GPJA			NYSE
Southern Power Company			Series 2016B 1.850% Senior Notes due 2026			SO/26A			NYSE

Indicate by check mark whether the registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. Yes þ No ¨

Indicate by check mark whether the registrants have submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrants were required to submit such files). Yes þ No ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Registrant			Large Accelerated Filer			Accelerated Filer			Non-accelerated Filer			Smaller Reporting Company			Emerging Growth Company
The Southern Company			X
Alabama Power Company									X
Georgia Power Company									X
Mississippi Power Company									X
Southern Power Company									X
Southern Company Gas									X

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No þ (Response applicable to all registrants.)

Registrant			Description of Common Stock			Shares Outstanding at June 30, 2026
The Southern Company			Par Value $0.01 Per Share			1,150,362,966
Alabama Power Company			Par Value $40 Per Share			30,537,500
Georgia Power Company			Without Par Value			9,261,500
Mississippi Power Company			Without Par Value			1,121,000
Southern Power Company			Par Value $0.01 Per Share			1,000
Southern Company Gas			Par Value $0.01 Per Share			100

This combined Form 10-Q is separately filed by The Southern Company, Alabama Power Company, Georgia Power Company, Mississippi Power Company, Southern Power Company, and Southern Company Gas. Information contained herein relating to any individual registrant is filed by such registrant on its own behalf. Each registrant makes no representation as to information relating to the other registrants.

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TABLE OF CONTENTS

						Page
			Definitions			4
			Cautionary Statement Regarding Forward-Looking Information			7
			PART I—FINANCIAL INFORMATION
Item 1.			Financial Statements (Unaudited)			9
Item 2.			Management's Discussion and Analysis of Financial Condition and Results of Operations			90
Item 3.			Quantitative and Qualitative Disclosures about Market Risk			139
Item 4.			Controls and Procedures			139
			PART II—OTHER INFORMATION
Item 1.			Legal Proceedings			140
Item 1A.			Risk Factors			140
Item 2.			Unregistered Sales of Equity Securities and Use of Proceeds			Inapplicable
Item 3.			Defaults Upon Senior Securities			Inapplicable
Item 4.			Mine Safety Disclosures			Inapplicable
Item 5.			Other Information			140
Item 6.			Exhibits			140
			Signatures			144

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DEFINITIONS

Term			Meaning
2022 ARP			Georgia Power's Alternate Rate Plan approved by the Georgia PSC in 2022 for the years 2023 through 2025
2023 IRP Update			Georgia Power's updated IRP filed in 2023 and approved by the Georgia PSC in 2024 as modified by a stipulation among Georgia Power, the staff of the Georgia PSC, and certain intervenors
2024 ELG Rule			Final rule published by the EPA in 2024 revising the steam effluent guidelines
AFUDC			Allowance for funds used during construction
AGL Services Company			AGL Services Company, Inc., the Southern Company Gas system service company and a wholly-owned subsidiary of Southern Company Gas
Alabama Power			Alabama Power Company
ARO			Asset retirement obligation
Atlanta Gas Light			Atlanta Gas Light Company, a wholly-owned subsidiary of Southern Company Gas
CAMT			Corporate alternative minimum tax
CCR			Coal combustion residuals
Chattanooga Gas			Chattanooga Gas Company, a wholly-owned subsidiary of Southern Company Gas
COD			Commercial operation date
CODM			Chief operating decision maker
CWIP			Construction work in progress
Dalton			City of Dalton, Georgia, an incorporated municipality in the state of Georgia, acting by and through its Board of Water, Light, and Sinking Fund Commissioners
Dalton Pipeline			A pipeline facility in Georgia in which Southern Company Gas has a 50% undivided ownership interest
DOE			U.S. Department of Energy
ECO Plan			Mississippi Power's environmental compliance overview plan
EPA			U.S. Environmental Protection Agency
EPS			Earnings per share
FCC			Federal Communications Commission
FERC			Federal Energy Regulatory Commission
FFB			Federal Financing Bank
Fitch			Fitch Ratings, Inc.
Form 10-K			Annual Report on Form 10-K of Southern Company, Alabama Power, Georgia Power, Mississippi Power, Southern Power, and Southern Company Gas for the year ended December 31, 2025, as applicable
GAAP			U.S. generally accepted accounting principles
Georgia Power			Georgia Power Company
Heating Degree Days			A measure of weather, calculated when the average daily temperatures are less than 65 degrees Fahrenheit
Heating Season			The period from November through March when Southern Company Gas' natural gas usage and operating revenues are generally higher
HLBV			Hypothetical liquidation at book value
IIC			Intercompany Interchange Contract
Illinois Commission			Illinois Commerce Commission
Internal Revenue Code			Internal Revenue Code of 1986, as amended
IRA			Inflation Reduction Act of 2022
IRP			Integrated resource plan
ITC			Investment tax credit
Jurisdictional Separation Study Order			Authorization from the Alabama PSC in June 2025 for Alabama Power to defer certain costs associated with capacity previously allocated to wholesale electric services that is now being used for retail electric service
KWH			Kilowatt-hour

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DEFINITIONS

(continued)

Term			Meaning
LIFO			Last-in, first-out
LTSA			Long-term service agreement
MEAG Power			Municipal Electric Authority of Georgia
Mississippi Power			Mississippi Power Company
mmBtu			Million British thermal units
Moody's			Moody's Investors Service, Inc.
MRA			Municipal and Rural Associations
MW			Megawatt
natural gas distribution utilities			Southern Company Gas' natural gas distribution utilities (Nicor Gas, Atlanta Gas Light, Virginia Natural Gas, and Chattanooga Gas)
NDR			Alabama Power's Natural Disaster Reserve
Nicor Gas			Northern Illinois Gas Company, a wholly-owned subsidiary of Southern Company Gas
N/M			Not meaningful
NRC			U.S. Nuclear Regulatory Commission
OBBB			One Big Beautiful Bill Act
OCI			Other comprehensive income
OPC			Oglethorpe Power Corporation (an electric membership corporation)
PEP			Mississippi Power's Performance Evaluation Plan
PowerSecure			PowerSecure, Inc., a wholly-owned subsidiary of Southern Company
PPA			Power purchase agreements, as well as, for Southern Power, contracts for differences that provide the owner of a renewable facility a certain fixed price for the electricity sold to the grid
PSC			Public Service Commission
PTC			Production tax credit
Rate CNP			Alabama Power's Rate Certificated New Plant, consisting of Rate CNP New Plant, Rate CNP Compliance, Rate CNP PPA, and Rate CNP Depreciation
Rate ECR			Alabama Power's Rate Energy Cost Recovery
Rate RSE			Alabama Power's Rate Stabilization and Equalization
Registrants			Southern Company, Alabama Power, Georgia Power, Mississippi Power, Southern Power Company, and Southern Company Gas
ROE			Return on equity
S&P			S&P Global Ratings, a division of S&P Global Inc.
SCS			Southern Company Services, Inc., the Southern Company system service company and a wholly-owned subsidiary of Southern Company
SEC			U.S. Securities and Exchange Commission
SEGCO			Southern Electric Generating Company, 50% owned by each of Alabama Power and Georgia Power
SNG			Southern Natural Gas Company, L.L.C., a pipeline system in which Southern Company Gas has a 50% ownership interest
SOFR			Secured Overnight Financing Rate
Southern Company			The Southern Company
Southern Company Gas			Southern Company Gas and its subsidiaries
Southern Company Gas Capital			Southern Company Gas Capital Corporation, a wholly-owned subsidiary of Southern Company Gas
Southern Company power pool			The operating arrangement whereby the integrated generating resources of the traditional electric operating companies and Southern Power (excluding subsidiaries) are subject to joint commitment and dispatch in order to serve their combined load obligations
Southern Company system			Southern Company, the traditional electric operating companies, Southern Power, Southern Company Gas, SEGCO, Southern Nuclear, SCS, Southern Linc, PowerSecure, and other subsidiaries
Southern Holdings			Southern Company Holdings, Inc., a wholly-owned subsidiary of Southern Company

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DEFINITIONS

(continued)

Term			Meaning
Southern Linc			Southern Communications Services, Inc., a wholly-owned subsidiary of Southern Company, doing business as Southern Linc
Southern Nuclear			Southern Nuclear Operating Company, Inc., a wholly-owned subsidiary of Southern Company
Southern Power			Southern Power Company and its subsidiaries
SouthStar			SouthStar Energy Services, LLC (a Marketer), a wholly-owned subsidiary of Southern Company Gas
SP Solar			SP Solar Holdings I, LP, a limited partnership indirectly owning substantially all of Southern Power's solar and battery energy storage facilities, in which Southern Power has a 67% ownership interest
SP Wind			SP Wind Holdings II, LLC, a holding company owning a portfolio of eight operating wind facilities and wholly owned by Southern Power as of December 31, 2025, was previously in a tax equity arrangement where Southern Power was the controlling partner through December 31, 2025
SRR			Mississippi Power's System Restoration Rider, a tariff for retail property damage cost recovery and reserve
Subsidiary Registrants			Alabama Power, Georgia Power, Mississippi Power, Southern Power, and Southern Company Gas
Tax Reform Legislation			The Tax Cuts and Jobs Act, which became effective on January 1, 2018
traditional electric operating companies			Alabama Power, Georgia Power, and Mississippi Power
U.S. Treasury			U.S. Department of the Treasury
VIE			Variable interest entity
Virginia Natural Gas			Virginia Natural Gas, Inc., a wholly-owned subsidiary of Southern Company Gas
Vogtle Owners			Georgia Power, OPC, MEAG Power, and Dalton

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING INFORMATION

This Quarterly Report on Form 10-Q contains forward-looking statements. Forward-looking statements include, among other things, statements concerning regulated rates, the strategic goals for the business, customer and sales growth, economic conditions, including interest rates, tariffs, and inflation, cost recovery and other rate actions, current and proposed environmental regulations and related compliance plans and estimated expenditures, pending or potential litigation matters, access to sources of capital, financing activities, completion dates and costs of construction projects, filings with state and federal regulatory authorities, and estimated construction plans and expenditures. In some cases, forward-looking statements can be identified by terminology such as "may," "will," "could," "would," "should," "expects," "plans," "anticipates," "believes," "estimates," "projects," "predicts," "potential," or "continue" or the negative of these terms or other similar terminology. There are various factors that could cause actual results to differ materially from those suggested by the forward-looking statements; accordingly, there can be no assurance that such indicated results will be realized. These factors include:

• the impact of recent and future federal and state legal and regulatory changes, including tax, environmental, and other laws and regulations to which Southern Company and its subsidiaries are subject, as well as changes in application of existing laws, regulations, and guidance;

• the extent and timing of costs and legal requirements related to CCR;

• current and future litigation or regulatory investigations, proceedings, or inquiries;

• the effects, extent, and timing of the entry of additional competition in the markets in which Southern Company's subsidiaries operate, including from the development and deployment of alternative energy sources;

• variations in demand for electricity and natural gas, including uncertainties related to projected significant growth in electricity demand driven primarily by data centers and other large load customers, and the related requirement for substantial new generation and transmission investments, creating capital access and revenue recovery risks for the traditional electric operating companies;

• customer affordability matters;

• available sources and costs of natural gas and other fuels and commodities;

• the ability to complete necessary or desirable pipeline expansion or infrastructure projects, limits on pipeline capacity, public and policymaker support for such projects, and operational interruptions to natural gas distribution and transmission activities;

• transmission constraints;

• the ability to control costs and avoid cost and schedule overruns during the development, construction, and operation of facilities or other projects due to challenges which include, but are not limited to, changes in labor costs, availability, and productivity; challenges with the management of contractors or vendors; subcontractor performance; adverse weather conditions; shortages, delays, increased costs, or inconsistent quality of equipment, materials, and labor; contractor or supplier delay; the impacts of inflation and trade policies (including tariffs and other trade measures) of the United States and other countries; delays due to judicial or regulatory action; nonperformance under construction, operating, or other agreements; operational readiness, including specialized operator training and required site safety programs; engineering or design problems or any remediation related thereto; design and other licensing-based compliance matters; challenges with start-up activities, including major equipment failure, or system integration, and/or operational performance; challenges related to future epidemic or pandemic health events; continued public and policymaker support for projects; environmental and geological conditions; delays or increased costs to interconnect facilities to transmission grids; and increased financing costs as a result of changes in interest rates or as a result of project delays;

• legal proceedings and regulatory approvals and actions related to past, ongoing, and proposed construction projects, including state PSC or other applicable state regulatory agency approvals and FERC and NRC actions;

• the ability to construct facilities in accordance with the requirements of permits and licenses, to satisfy any environmental performance standards and the requirements of tax credits and other incentives, and to integrate facilities into the Southern Company system upon completion of construction;

• investment performance of the employee and retiree benefit plans and nuclear decommissioning trust funds and, with respect to retiree benefit plans, changes in actuarial assumptions and differences between the assumptions and actual values, any of the foregoing of which could cause additional funding requirements;

• advances in technology, including the pace and extent of development of low- to no-carbon energy and battery energy storage technologies and the impact of advancing technology on data center and other large load customer demand;

• performance of counterparties under ongoing renewable energy partnerships and development agreements;

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING INFORMATION

(continued)

• state and federal rate regulations and the impact of pending and future rate cases and negotiations, including rate actions relating to ROE, equity ratios, additional generating capacity and transmission facilities, extension of retirement dates for fossil fuel plants, and fuel and other cost recovery mechanisms;

• the ability to successfully operate the traditional electric operating companies', SEGCO's, and Southern Power's generation, transmission, distribution, and battery energy storage facilities, as applicable, and Southern Company Gas' natural gas distribution and storage facilities and the successful performance of necessary corporate functions;

• the inherent risks involved in operating nuclear generating facilities;

• the inherent risks involved in generation, transmission, and distribution of electricity and transportation and storage of natural gas, including accidents, explosions, fires, mechanical problems, discharges or releases of toxic or hazardous substances or gases, and other environmental risks;

• the performance of projects undertaken by the non-utility businesses and the success of efforts to invest in and develop new opportunities;

• internal restructuring or other restructuring options that may be pursued;

• potential business strategies, including acquisitions or dispositions of assets or businesses, or interests therein, which cannot be assured to be completed or beneficial to Southern Company or its subsidiaries;

• the ability of counterparties of Southern Company and its subsidiaries to make payments as and when due and to perform as required;

• the ability to obtain new short- and long-term contracts with wholesale customers;

• the direct or indirect effect on the Southern Company system's business resulting from cyber intrusion or physical attack and the threat of cyber and physical attacks;

• global and U.S. economic conditions, including impacts from geopolitical conflicts, recession, inflation, changes in trade policies (including tariffs and other trade measures) of the United States and other countries, interest rate fluctuations, and financial market conditions, and the results of financing efforts;

• prolonged or recurring U.S. federal government shutdowns;

• access to capital markets and other financing sources;

• changes in Southern Company's and any of its subsidiaries' credit ratings;

• the ability of the traditional electric operating companies to obtain additional generating capacity (or sell excess generating capacity) at competitive prices;

• catastrophic events such as fires, including wildfires, land movement, earthquakes, explosions, floods, high winds, tornadoes, hurricanes and other storms, solar flares, droughts, future epidemic or pandemic health events, wars, political unrest, or other similar occurrences;

• the direct or indirect effects on the Southern Company system's business resulting from incidents affecting the U.S. electric grid, natural gas pipeline infrastructure, or operation of generating or storage resources;

• impairments of goodwill or long-lived assets;

• the effect of accounting pronouncements issued periodically by standard-setting bodies; and

• other factors discussed elsewhere herein and in other reports (including the Form 10-K) filed by the Registrants from time to time with the SEC.

The Registrants expressly disclaim any obligation to update any forward-looking statements.

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PART I