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): July 30, 2010

SIMON PROPERTY GROUP, INC.

(Exact name of registrant as specified in its charter)

Registrant's telephone number, including area code: 317.636.1600

Not Applicable
(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act
(17 CFR 240.14d-2(b))

o

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act
(17 CFR 240.13e-4(c))

---

Item 2.02.    Results of Operations and Financial Condition

        On July 30, 2010, Simon Property Group, Inc. (the "Registrant") issued a press release containing information on earnings for the quarter ended June 30, 2010 and other matters. A copy of the press release is attached hereto as Exhibit 99.2 and the information in the press release is incorporated by reference into this report.

        The Registrant is furnishing the information contained herein, including Exhibit 99.2, pursuant to Item 2.02 of Form 8-K promulgated by the Securities and Exchange Commission (the "SEC"). This information shall not be deemed to be "filed" with the SEC or incorporated by reference into any other filing with the SEC.

Item 7.01.    Regulation FD Disclosure

        On July 30, 2010, the Registrant made available additional ownership and operational information concerning the Registrant, Simon Property Group, L.P., and properties owned or managed as of June 30, 2010 in the form of a Supplemental Information package, a copy of which is attached as Exhibit 99.1. The Supplemental Information package is also available upon request as specified therein.

        The Registrant is furnishing the information contained herein, including Exhibit 99.1, pursuant to Item 7.01 of Form 8-K promulgated by the SEC. This information shall not be deemed to be "filed" with the SEC or incorporated by reference into any other filing with the SEC.

        This report contains measures of financial or operating performance that are not specifically defined by accounting principles generally accepted in the United States ("GAAP"), including funds from operations ("FFO"), FFO as adjusted, diluted FFO per share, diluted FFO per share as adjusted, net operating income ("NOI"), and diluted earnings per share as adjusted. FFO and NOI are performance measures that are standard in the REIT business. We believe FFO and NOI provide investors with additional information concerning our operating performance and a basis to compare our performance with those of other REITs. We also use these measures internally to monitor the operating performance of our portfolio. FFO as adjusted, diluted FFO per share as adjusted, and diluted earnings per share as adjusted measures exclude the effect of certain non-cash impairment and debt-related charges. We believe these measures provide investors with a basis to compare our current operating performance with previous periods in which we did not have those charges. Our computation of these non-GAAP measures may not be the same as similar measures reported by other REITs.

        The non-GAAP financial measures used in this report should not be considered as alternatives to net income as a measure of our operating performance or to cash flows computed in accordance with GAAP as a measure of liquidity nor are they indicative of cash flows from operating, conducting and financial activities.

        Reconciliations of each of the non-GAAP measures used in this report to the most-directly comparable GAAP measure are included.

Item 9.01.    Financial Statements and Exhibits

        Financial Statements:

None

        Exhibits:

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: July 30, 2010

3

---

SIMON PROPERTY GROUP
Table of Contents
As of June 30, 2010

4

---

QuickLinks

Item 2.02. Results of Operations and Financial Condition
Item 7.01. Regulation FD Disclosure
Item 9.01. Financial Statements and Exhibits

SIGNATURES
SIMON PROPERTY GROUP Table of Contents As of June 30, 2010