QuickLinks -- Click here to rapidly navigate through this document SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 17, 2002 (May 8, 2002) SIMON PROPERTY GROUP, INC. (Exact name of registrant as specified in its charter) Delaware 001-14469 046268599 (State or other jurisdiction (Commission (IRS Employer of incorporation) File Number) Identification No.) 115 WEST WASHINGTON STREET 46204 INDIANAPOLIS, INDIANA (Zip Code) (Address of principal executive offices) Registrant's telephone number, including area code: 317.636.1600 Not Applicable (Former name or former address, if changed since last report) Item 5. Other Events On May 8, 2002, the Registrant issued a press release containing information on earnings for the quarter ended March 31, 2002 and other matters. A copy of the press release is included as an exhibit to this filing. On May 9, 2002, the Registrant held a conference call to discuss earnings for the quarter ended March 31, 2002 and other matters. A transcript of this conference call is included as an exhibit to this filing. On May 17, 2002, the Registrant made available additional ownership and operation information concerning the Registrant, SPG Realty Consultants, Inc. (the Registrant's paired-share affiliate), Simon Property Group, L.P., and properties owned or managed as of March 31, 2002, in the form of a Supplemental Information package, a copy of which is included as an exhibit to this filing. The Supplemental Information package is available upon request as specified therein. Item 7. Financial Statements and Exhibits Financial Statements: None Exhibits: Exhibit Page Number in No. Description This Filing 99.1 Supplemental Information as of March 31, 2002 5 99.2 Earnings Release for the quarter ended March 31, 2002 36 99.3 Teleconference Text for the quarter ended March 31, 2002 42 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. Dated: May 17, 2002 SIMON PROPERTY GROUP, INC. By: /s/ STEPHEN E. STERRETT Stephen E. Sterrett, Executive Vice President and Chief Financial Officer 3 SIMON PROPERTY GROUP Table of Contents As of March 31, 2002 Description Page Exhibit 99.1 Supplemental Information Overview 5 Ownership Structure 6-8 Reconciliation of Income to Funds from Operations ("FFO") 9 Selected Financial Information 10-11 Portfolio GLA, Occupancy & Rent Data 12 Rent Information 13 Lease Expirations 14-15 Debt Amortization and Maturities by Year 16 Summary of Indebtedness 17 Summary of Indebtedness by Maturity 18-25 Summary of Variable Rate Debt and Interest Rate Protection Agreements 26-27 Significant Renovation/Expansion Activities 28 Capital Expenditures 29 Property Listing 30-35 Exhibit 99.2 Press Release 36-41 Exhibit 99.3 Teleconference Text—May 9, 2002 42-47 4 QuickLinks SIGNATURES SIMON PROPERTY GROUP Table of Contents As of March 31, 2002 QuickLinks -- Click here to rapidly navigate through this document SIMON PROPERTY GROUP Overview The Company Simon Property Group, Inc. ("SPG") (NYSE:SPG) is a self-administered and self-managed real estate investment trust ("REIT"). Simon Property Group, L.P. (the "Operating Partnership") is a subsidiary partnership of SPG. Shares of SPG are paired with beneficial interests in shares of stock of SPG Realty Consultants, Inc. ("SRC", and together with SPG, the "Company"). The Company and the Operating Partnership (collectively the "Simon Group") are engaged primarily in the ownership, operation, management, leasing, acquisition, expansion and development of real estate properties, primarily regional malls and community shopping centers. At March 31, 2002, the Company, directly or through the Operating Partnership, owned or had an interest in 251 properties which consisted of regional malls, community shopping centers, and specialty and mixed-use properties containing an aggregate of 186.8 million square feet of gross leasable area (GLA) in 36 states and eight assets in Europe and Canada. On January 13, 2002, the Company announced a joint agreement with The Rouse Company and Westfield America Trust to purchase the assets of Rodamco North America N.V. (RNA) for $5.3 billion. The transaction was completed on May 3, 2002. The portfolio acquired by the Company consists primarily of interests in 13 high-quality, highly-productive regional malls in the United States, as well as ownership interests in other real estate assets. The Company's share of the RNA purchase price was approximately $1.59 billion, including the assumption of $579 million of property-level debt and preferred stock. This package was prepared to provide (1) ownership information, (2) certain operational information, and (3) debt information as of March 31, 2002, for the Company and the Operating Partnership. Certain statements contained in this Supplemental Package may constitute "forward-looking statements" made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Readers are cautioned that forward-looking statements involve risks and uncertainties, which may affect the business and prospects of the Company and the Operating Partnership. We direct you to the Company's various filings with the Securities and Exchange Commission including Form 10-K and Form 10-Q for a detailed discussion of risks and uncertainties. We hope you find this Supplemental Package beneficial. Any questions, comments or suggestions should be directed to: Shelly J. Doran, Vice President of Investor Relations-Simon Property Group, P.O. Box 7033, Indianapolis, IN 46207. Telephone: (317) 685-7330; e- mail: [email protected] 5 Simon Property Group Economic Ownership Structure(1) March 31, 2002 (1) Schedule excludes preferred stock (see "Preferred Stock/Units Outstanding") and units not convertible into common stock. (2) Managing general partner of Simon Property Group, L.P. (3) Shares of Simon Property Group, Inc. ("SPG") are paired with beneficial interests in shares of stock of SPG Realty Consultants, Inc. (4) The number of outstanding shares of common stock of SPG exceeds the number of Simon Property Group, L.P. units owned by SPG by 1,670,944. This is the result of the direct ownership of Ocean County Mall by SPG, partially offset by units issued to SPG in exchange for Northshore Mall. (5) Executive management excludes Simon family members. 6 SIMON PROPERTY GROUP Changes in Common Shares and Unit Ownership For the Period from December 31, 2001 through March 31, 2002 Operating Partnership Company Units(1) Common Shares(2) Number Outstanding at December 31, 2001 63,930,350 173,806,306 Issuance of Stock for Stock Option Exercises — 323,723 Conversion of Units into Common Stock (100,000) 100,000 Conversion of Units into Cash (345) — Number Outstanding at March 31, 2002 63,830,005 174,230,029 Total Common Shares and Units Outstanding at March 31, 2002: 238,060,034(2) Details for Diluted Common Shares Outstanding: Company Common Shares Outstanding at March 31, 2002 174,230,029 Number of Common Shares Issuable Assuming Conversion of: Series A Preferred 6.5% Convertible(3) 1,893,651 Series B Preferred 6.5% Convertible(3) 12,490,773 Net Number of Common Shares Issuable Assuming Exercise of Stock Options(4) 582,718 Diluted Common Shares Outstanding at March 31, 2002 189,197,171 Fully Diluted Common Shares and Units Outstanding at March 31, 2002: 253,027,176 (1) Excludes units owned by the Company (shown here as Company Common Shares) and units not convertible into common shares. (2) Excludes preferred units relating to preferred stock outstanding (see Schedule of Preferred Stock Outstanding). (3) Conversion terms provided in footnotes (1) and (2) on page 8 of this document. (4) Based upon the weighted average stock price for the first quarter of 2002. 7 SIMON PROPERTY GROUP Preferred Stock/Units Outstanding As of March 31, 2002 ($ in 000's) Per Share Aggregate Number of Liquidation Liquidation Ticker Issuer Description Shares/Units Preference Preference Symbol Preferred Shares: Convertible Simon Property Group, Inc. Series A Preferred 49,839 $ 1,000 $ 49,839 N/A 6.5% Convertible(1) Simon Property Group, Inc. Series B Preferred 4,830,057 $ 100 $ 483,006 SPGPrB 6.5% Convertible(2) Perpetual Simon Property Group, Inc. Series E Preferred 8% 1,000,000 $ 25 $ 25,000 N/A Cumulative Redeemable(3) Simon Property Group, Inc. Series F Preferred 8,000,000 $ 25 $ 200,000 SPGPrF 3 8 /4% Perpetual(4) Simon Property Group, Inc. Series G Preferred 3,000,000 $ 50 $ 150,000 SPGPrG 7.89% Perpetual(5) Preferred Units: Simon Property Group, L.P. Series C 7% 2,600,895 $ 28 $ 72,825 N/A Cumulative Convertible Preferred(6) Simon Property Group, L.P. Series D 8% 2,600,895 $ 30 $ 78,027 N/A Cumulative Redeemable Preferred(7) (1) Assumed in connection with the CPI merger. Each share is convertible into a number of shares of common stock obtained by dividing $1,000 by $26.319 (conversion price), which is subject to adjustment as outlined below. The stock is not redeemable, except as needed to maintain or bring the direct or indirect ownership of the capital stock of the Company into conformity with the requirements of Section 856(a)(6) of the Code. (2) Issued as part of the consideration for the CPI merger. Each share is convertible into a number of shares of common stock of the Company obtained by dividing $100 by $38.669 (the conversion price), which is subject to adjustment as outlined below. The Company may redeem the stock on or after September 24, 2003 at a price beginning at 105% of the liquidation preference plus accrued dividends and declining to 100% of the liquidation preference plus accrued dividends any time on or after September 24, 2008.