Item 1A. Risk Factors

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The following factors, among others, could cause our actual results to differ materially from those contained in forward-looking statements made in this Annual Report on Form 10-K and presented elsewhere by our management from time to time. These factors may have a material adverse effect on our business, financial condition, operating results and cash flows, and you should carefully consider them. Additional risks and uncertainties not presently known to us or which are currently not believed to be material may also affect our actual results. We may update these factors in our future periodic reports.

Risks Relating to Debt and the Financial Markets

We have a substantial debt burden that could affect our future operations.

As of December 31, 2014, our consolidated mortgages and unsecured indebtedness, excluding related premium and discount, totaled $20.8 billion. We are subject to the risks normally associated with debt financing, including the risk that our cash flow from operations will be insufficient to meet required debt service. Our debt service costs generally will not be reduced if developments at the property, such as the entry of new competitors or the loss of major tenants, cause a reduction in the income from the property. Should such events occur, our operations may be adversely affected. If a property is mortgaged to secure payment of indebtedness and income from such property is insufficient to pay that indebtedness, the property could be foreclosed upon by the mortgagee resulting in a loss of income and a decline in our total asset value.

Disruption in the credit markets or downgrades in our credit ratings may adversely affect our ability to access external financings for our growth and ongoing debt service requirements.

We depend on external financings, principally debt financings, to fund the growth of our business and to ensure that we can meet ongoing maturities of our outstanding debt. Our access to financing depends on our credit rating, the willingness of banks to lend to us and conditions in the capital markets. We cannot assure you that we will be able to obtain the financing we need for future growth or to meet our debt service as obligations mature, or that the financing available to us will be on acceptable terms.

Adverse changes in our credit rating could affect our borrowing capacity and borrowing terms.

The Operating Partnership's outstanding senior unsecured notes, the Commercial Paper program, and Simon's preferred stock are periodically rated by nationally recognized credit rating agencies. The credit ratings are based on our operating performance, liquidity and leverage ratios, overall financial position, and other factors viewed by the credit rating agencies as relevant to our industry and the economic outlook in general. Our credit rating can affect the amount of capital we can access, as well as the terms of any financing we obtain. Since we depend primarily on debt financing to fund our growth, adverse changes in our credit rating could have a negative effect on our future growth.

Our hedging interest rate protection arrangements may not effectively limit our interest rate risk.

We selectively manage our exposure to interest rate risk by a combination of interest rate protection agreements to effectively fix or cap a portion of our variable rate debt. In addition, we refinance fixed rate debt at times when we believe rates and terms are appropriate. Our efforts to manage these exposures may not be successful.

Our use of interest rate hedging arrangements to manage risk associated with interest rate volatility may expose us to additional risks, including a risk that a counterparty to a hedging arrangement may fail to honor its obligations. Developing an effective interest rate risk strategy is complex and no strategy can completely insulate us from risks associated with interest rate fluctuations. There can be no assurance that our hedging activities will have the desired beneficial impact on our results of operations or financial condition. Termination of these hedging agreements typically involves costs, such as transaction fees or breakage costs.

Factors Affecting Real Estate Investments and Operations

We face risks associated with the acquisition, development, redevelopment and expansion of properties.

We regularly acquire and develop new properties and expand and redevelop existing properties, and these activities are subject to various risks. We may not be successful in pursuing acquisition, development or redevelopment/expansion opportunities. In addition, newly acquired, developed or redeveloped/expanded properties may not perform as well as

expected. We are subject to other risks in connection with any acquisition, development and redevelopment/expansion activities, including the following:

construction costs of a project may be higher than projected, potentially making the project unfeasible or unprofitable;

we may not be able to obtain financing or to refinance loans on favorable terms, if at all;

we may be unable to obtain zoning, occupancy or other governmental approvals;

occupancy rates and rents may not meet our projections and the project may not be profitable; and

we may need the consent of third parties such as department stores, anchor tenants, mortgage lenders and joint venture partners, and those consents may be withheld.

If a development or redevelopment/expansion project is unsuccessful, either because it is not meeting our expectations when operational or was not completed according to the project planning, we could lose our investment in the project. Further, if we guarantee the property's financing, our loss could exceed our investment in the project.

Real estate investments are relatively illiquid.

Our properties represent a substantial portion of our total consolidated assets. These investments are relatively illiquid. As a result, our ability to sell one or more of our properties or investments in real estate in response to any changes in economic or other conditions may be limited. If we want to sell a property, we cannot assure you that we will be able to dispose of it in the desired time period or that the sales price of a property will exceed the cost of our investment.

Our international expansion may subject us to different or greater risk from those associated with our domestic operations.

As of December 31, 2014, we held interests in joint venture properties that operate in Austria, Italy, Japan, Malaysia, Mexico, the Netherlands, South Korea, Canada, and the United Kingdom. We also have an equity stake in Klépierre, a publicly-traded European real estate company which operates in 13 countries in Europe. Accordingly, our operating results and the value of our international operations may be impacted by any unhedged movements in the foreign currencies in which those operations transact and in which our net investment in the foreign operation is held. We may pursue additional expansion and development opportunities outside the United States. International development and ownership activities carry risks that are different from those we face with our domestic properties and operations. These risks include:

adverse effects of changes in exchange rates for foreign currencies;

changes in foreign political and economic environments, regionally, nationally, and locally;

challenges of complying with a wide variety of foreign laws including corporate governance, operations, taxes, and litigation;

differing lending practices;

differences in cultures;

changes in applicable laws and regulations in the United States that affect foreign operations;

difficulties in managing international operations; and

obstacles to the repatriation of earnings and cash.

Our international activities represented approximately 9.0% of our net operating income, or NOI, for the year ended December 31, 2014. To the extent that we expand our international activities, the above risks could increase in significance, which in turn could have an adverse effect on our results of operations and financial condition.

Environmental Risks

As owners of real estate, we can face liabilities for environmental contamination.

Federal, state and local laws and regulations relating to the protection of the environment may require us, as a current or previous owner or operator of real property, to investigate and clean up hazardous or toxic substances or petroleum product releases at a property or at impacted neighboring properties. These laws often impose liability regardless of whether the property owner or operator knew of, or was responsible for, the presence of hazardous or toxic

substances. These laws and regulations may require the abatement or removal of asbestos containing materials in the event of damage, demolition or renovation, reconstruction or expansion of a property and also govern emissions of and exposure to asbestos fibers in the air. Those laws and regulations also govern the installation, maintenance and removal of underground storage tanks used to store waste oils or other petroleum products. Many of our properties contain, or at one time contained, asbestos containing materials or underground storage tanks (primarily related to auto service center establishments or emergency electrical generation equipment). The costs of investigation, removal or remediation of hazardous or toxic substances may be substantial and could adversely affect our results of operations or financial condition but is not estimable. The presence of contamination, or the failure to remediate contamination, may also adversely affect our ability to sell, lease or redevelop a property or to borrow using a property as collateral.

Our efforts to identify environmental liabilities may not be successful.

Although we believe that our portfolio is in substantial compliance with federal, state and local environmental laws, ordinances and regulations regarding hazardous or toxic substances, this belief is based on limited testing. Nearly all of our properties have been subjected to Phase I or similar environmental audits. These environmental audits have not revealed, nor are we aware of, any environmental liability that we believe will have a material adverse effect on our results of operations or financial condition. However, we cannot assure you that:

existing environmental studies with respect to the portfolio reveal all potential environmental liabilities;

any previous owner, occupant or tenant of a property did not create any material environmental condition not known to us;

the current environmental condition of the portfolio will not be affected by tenants and occupants, by the condition of nearby properties, or by other unrelated third parties; or

future uses or conditions (including, without limitation, changes in applicable environmental laws and regulations or the interpretation thereof) will not result in environmental liabilities.

Retail Operations Risks

Overall economic conditions may adversely affect the general retail environment.

Our concentration in the retail real estate market means that we are subject to the risks that affect the retail environment generally, including the levels of consumer spending, seasonality, the willingness of retailers to lease space in our shopping centers, tenant bankruptcies, changes in economic conditions, increasing use of the internet by retailers and consumers, consumer confidence, casualties and other natural disasters, and the potential for terrorist activities. The economy and consumer spending appear to be recovering from the effects of the recent recession. We derive our cash flow from operations primarily from retail tenants, many of whom have been and continue to be under some degree of economic stress. A significant deterioration in our cash flow from operations could require us to curtail planned capital expenditures or seek alternative sources of financing.

We may not be able to lease newly developed properties and renew leases and relet space at existing properties.

We may not be able to lease new properties to an appropriate mix of tenants or for rents that are consistent with our projections. Also, when leases for our existing properties expire, the premises may not be relet or the terms of reletting, including the cost of allowances and concessions to tenants, may be less favorable than the current lease terms. To the extent that our leasing plans are not achieved, our cash generated before debt repayments and capital expenditures could be adversely affected. Changes in economic and operating conditions that occur subsequent to our review of recoverability of investment property and other assets could impact the assumptions used in that assessment and could result in future charges to earnings if assumptions regarding those investments differ from actual results.

Some of our properties depend on anchor stores or major tenants to attract shoppers and could be adversely affected by the loss of one or more of these anchor stores or major tenants.

Our properties are typically anchored by department stores and other large nationally recognized tenants. The value of some of our properties could be materially adversely affected if these department stores or major tenants fail to comply with their contractual obligations or cease their operations.

For example, among department stores and other large stores — often referred to as "big box" stores — corporate merger activity typically results in the closure of duplicate or geographically overlapping store locations. Further sustained

adverse pressure on the results of our department stores and major tenants may have a similarly sustained adverse impact upon our own results. Certain department stores and other national retailers have experienced, and may continue to experience for the foreseeable future given current macroeconomic uncertainty and less-than-desirable levels of consumer confidence, considerable decreases in customer traffic in their retail stores, increased competition from alternative retail options such as those accessible via the Internet and other forms of pressure on their business models. As pressure on these department stores and national retailers increases, their ability to maintain their stores, meet their obligations both to us and to their external lenders and suppliers, withstand takeover attempts by investors or rivals or avoid bankruptcy and/or liquidation may be impaired and result in closures of their stores. Other tenants may be entitled to modify the economic or other terms of their existing leases in the event of such closures. The modification could be unfavorable to us as the lessor, and could decrease rents or expense recovery charges.

Additionally, department store or major tenant closures may result in decreased customer traffic, which could lead to decreased sales at our properties. If the sales of stores operating in our properties were to decline significantly due to the closing of anchor stores or other national retailers, adverse economic conditions, or other reasons, tenants may be unable to pay their minimum rents or expense recovery charges. In the event of any default by a tenant, we may not be able to fully recover, and/or may experience delays and costs in enforcing our rights as landlord to recover, amounts due to us under the terms of our agreements with such parties.

We face potential adverse effects from tenant bankruptcies.

Bankruptcy filings by retailers can occur regularly in the course of our operations. We continually seek to re-lease vacant spaces resulting from tenant terminations. The bankruptcy of a tenant, particularly an anchor tenant, may make it more difficult to lease the remainder of the affected properties. Future tenant bankruptcies could adversely affect our properties or impact our ability to successfully execute our re-leasing strategy.

We face a wide range of competition that could affect our ability to operate profitably.

Our properties compete with other retail properties and other forms of retailing such as catalogs and e-commerce websites. Competition may come from malls, outlet centers, community/lifestyle centers, and other shopping centers, both existing as well as future development projects, as well as catalogs and e-commerce. The presence of competitive alternatives affects our ability to lease space and the level of rents we can obtain. New construction, renovations and expansions at competing sites could also negatively affect our properties.

We also compete with other retail property developers to acquire prime development sites. In addition, we compete with other retail property companies for tenants and qualified management.

Risks Relating to Joint Venture Properties and our Investment in Klépierre

We have limited control with respect to some properties that are partially owned or managed by third parties, which may adversely affect our ability to sell or refinance them.

As of December 31, 2014, we owned interests in 95 income-producing properties with other parties. Of those, 13 properties are included in our consolidated financial statements. We account for the other 82 properties, or the joint venture properties, as well as our investment in Klépierre, using the equity method of accounting. We serve as general partner or property manager for 60 of these 82 properties; however, certain major decisions, such as approving the operating budget and selling, refinancing and redeveloping the properties require the consent of the other owners. Of the properties for which we do not serve as general partner or property manager, 19 are in our international joint ventures. The international properties are managed locally by joint ventures in which we share control of the properties with our partner. The other owners have participating rights that we consider substantive for purposes of determining control over the properties' assets. The remaining joint venture properties and Klépierre are managed by third parties. These limitations may adversely affect our ability to sell, refinance, or otherwise operate these properties.

The Operating Partnership guarantees debt or otherwise provides support for a number of joint venture properties.

Joint venture debt is the liability of the joint venture and is typically secured by a mortgage on the joint venture property, which is non-recourse to us. As of December 31, 2014, the Operating Partnership guaranteed joint venture related mortgage indebtedness of $223.5 million (of which we have a right of recovery from our venture partners of $78.7 million). A default by a joint venture under its debt obligations may expose us to liability under a guaranty. We may elect to fund cash needs of a joint venture through equity contributions (generally on a basis proportionate to our ownership interests), advances or partner loans, although such fundings are not typically required contractually or otherwise.

Other Factors Affecting Our Business

Some of our potential losses may not be covered by insurance.

We maintain insurance coverage with third party carriers who provide a portion of the coverage for specific layers of potential losses including commercial general liability, fire, flood, extended coverage and rental loss insurance on all of our properties in the United States. The initial portion of coverage not provided by third party carriers is either insured through our wholly-owned captive insurance companies or other financial arrangements controlled by us. A third party carrier has, in turn, agreed to provide evidence of coverage for this layer of losses under the terms and conditions of the carrier's policy. A similar policy written through our captive insurance entities also provides initial coverage for property insurance and certain windstorm risks at the properties located in coastal windstorm locations.

There are some types of losses, including lease and other contract claims, which generally are not insured. If an uninsured loss or a loss in excess of insured limits occurs, we could lose all or a portion of the capital we have invested in a property, as well as the anticipated future revenue it could generate.

We currently maintain insurance coverage against acts of terrorism on all of our properties in the United States on an "all risk" basis in the amount of up to $1 billion. The current federal laws which provide this coverage are expected to operate through 2020. Despite the existence of this insurance coverage, any threatened or actual terrorist attacks where we operate could adversely affect our property values, revenues, consumer traffic and tenant sales.

We face risks associated with security breaches through cyber-attacks, cyber intrusions or otherwise, as well as other significant disruptions of our information technology (IT) networks and related systems.

We face risks associated with security breaches, whether through cyber-attacks or cyber intrusions over the Internet, malware, computer viruses, attachments to e-mails, persons inside our organization or persons with access to systems, and other significant disruptions of our IT networks and related systems. Our IT networks and related systems are essential to the operation of our business and our ability to perform day-to-day operations and, in some cases, may be critical to the operations of certain of our tenants. Although we make efforts to maintain the security and integrity of these types of IT networks and related systems, and we have implemented various measures to manage the risk of a security breach or disruption, there can be no assurance that our security efforts and measures will be effective or that attempted security breaches or disruptions would not be successful or damaging. Even the most well protected information, networks, systems and facilities remain potentially vulnerable because the techniques used in such attempted security breaches evolve and generally are not recognized until launched against a target, and in some cases are designed not be detected and, in fact, may not be detected. Accordingly, we may be unable to anticipate these techniques or to implement adequate security barriers or other preventative measures, and thus it is impossible for us to entirely mitigate this risk.

Our success depends, in part, on our ability to attract and retain talented employees, and the loss of any one of our key personnel could adversely impact our business.

The success of our business depends, in part, on the leadership and performance of our executive management team and key employees, and our ability to attract, retain and motivate talented employees could significantly impact our future performance. Competition for these individuals is intense, and we cannot assure you that we will retain our executive management team and key employees or that we will be able to attract and retain other highly qualified individuals for these positions in the future. Losing any one or more of these persons could have a material adverse effect on our results of operations, financial condition and cash flows.

Risks Relating to Income Taxes

We have elected to be taxed as a REIT in the United States and certain of our international operations currently receive favorable tax treatment.

We are subject to certain income-based taxes, both domestically and internationally, and other taxes, including state and local taxes, franchise taxes, and withholding taxes on dividends from certain of our international investments. We currently receive favorable tax treatment in various domestic and international jurisdictions through tax rules and regulations or through international treaties. Should we no longer receive such benefits, the amount of taxes we pay may increase.

In the U.S., we have elected to be taxed as a REIT under Sections 856 through 860 of the Internal Revenue Code. We believe we have been organized and operated in a manner which allows us to qualify for taxation as a REIT under the Internal Revenue Code. We intend to continue to operate in this manner. However, our qualification and taxation as a REIT depend upon our ability to meet, through actual annual operating results, asset diversification, distribution levels and diversity of

stock ownership, the various qualification tests imposed under the Internal Revenue Code. REIT qualification is governed by highly technical and complex provisions for which there are only limited judicial or administrative interpretations. Accordingly, there is no assurance that we have operated or will continue to operate in a manner so as to qualify or remain qualified as a REIT.

If we fail to comply with those provisions, we may be subject to monetary penalties or ultimately to possible disqualification as a REIT. If such events occurs, and if available relief provisions do not apply:

we will not be allowed a deduction for distributions to stockholders in computing our taxable income;

we will be subject to corporate level income tax, including any applicable alternative minimum tax, on our taxable income at regular corporate rates; and

unless entitled to relief under relevant statutory provisions, we will also be disqualified from treatment as a REIT for the four taxable years following the year during which qualification was lost.