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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

Form 10-K/A

(Amendment No. 1)

For the fiscal year ended December 31, 2011

OR

For the transition period from              to             

Commission File No. 001-07511

STATE STREET CORPORATION

(Exact name of registrant as specified in its charter)

617-786-3000

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

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

None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  x    No  ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant (1) has 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 registrant was required to file such reports) and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  x

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

The aggregate market value of the voting and non-voting common equity held by non-affiliates computed by reference to the per share price ($45.09) at which the common equity was last sold as of the last business day of the registrant’s most recently completed second fiscal quarter (June 30, 2011) was approximately $22.40 billion.

The number of shares of the registrant’s common stock outstanding as of January 31, 2012 was 487,849,175.

Portions of the following documents are incorporated by reference into Parts of this Report on Form 10-K, to the extent noted in such Parts, as indicated below:

(1) The registrant’s definitive Proxy Statement for the 2012 Annual Meeting of Shareholders to be filed pursuant to Regulation 14A on or before April 30, 2012 (Part III).

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EXPLANATORY NOTE

This Amendment No. 1 on Form 10-K/A (“Amendment No. 1”) to our Annual Report on Form 10-K for the fiscal year ended December 31, 2011, which was filed with the Securities and Exchange Commission on February 27, 2012 (the “original
Form 10-K”), is being filed to revise Part III, Item 12 of the original Form 10-K. Part III, Item 12 of this Amendment No. 1 serves to incorporate by reference disclosure from our definitive proxy statement for the 2012 Annual Meeting of Shareholders filed with the Securities and Exchange Commission on or about the date hereof. The disclosure incorporated by reference is included in that definitive proxy statement under the caption “Item 3 - Approval of Amended and Restated 2006 Equity incentive Plan.”

In accordance with Rule 12b-15 under the Securities Exchange Act of 1934 (the “Exchange Act”), Part III, Item 12 of the original Form 10-K has been amended and restated in its entirety consistent with the above, and Part IV, Item 15 of the original Form 10-K has been amended and restated in its entirety, solely to include as exhibits the certifications under Exchange Act Rule 13a-14(a) required to be filed with this Amendment No. 1. This Amendment No. 1 does not amend or otherwise update any other information in the original Form 10-K. Accordingly, this Amendment No. 1 should be read in conjunction with the original Form 10-K and with our filings with the Securities and Exchange Commission subsequent to the original Form 10-K.

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STATE STREET CORPORATION

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PART III

Information concerning security ownership of certain beneficial owners and management will appear in our 2012 Proxy Statement under the caption “Security Ownership of Certain Beneficial Owners and Management.” Information concerning our equity compensation plans will appear in our 2012 Proxy Statement under the caption “Approval of Amended and Restated 2006 Equity Incentive Plan.” Such information is incorporated herein by reference.

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PART IV

(A)(2) FINANCIAL STATEMENT SCHEDULES

Certain schedules to the consolidated financial statements have been omitted if they were not required by Article 9 of Regulation S-X or if, under the related instructions, they were inapplicable, or the information was contained elsewhere in the original Form 10-K.

(A)(3) EXHIBITS

The exhibits listed in the Exhibit Index beginning on page 7 of this Amendment No. 1 are filed herewith in response to this Item or are incorporated herein by reference to other SEC filings.

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SIGNATURES

Pursuant to the requirement of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this Amendment No. 1 to be signed on its behalf by the undersigned, on April 5, 2012, thereunto duly authorized.

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EXHIBIT INDEX

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Attached as Exhibit 101 to the original Form 10-K are the following formatted in XBRL (Extensible Business Reporting Language): (i) Consolidated Statement of Income for the years ended December 31, 2011, 2010 and 2009, (ii) Consolidated Statement of Condition as of December 31, 2011 and 2010, (iii) Consolidated Statement of Changes in Shareholders’ Equity for the years ended December 31, 2011, 2010 and 2009, (iv) Consolidated Statement of Cash Flows for the years ended December 31, 2011, 2010 and 2009, and (v) Notes to Consolidated Financial Statements.

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