UNITED STATES

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): January 11, 2012

(Exact name of registrant as specified in its charter)

(Address of principal executive offices, including zip code)

Registrant’s telephone number, including area code: (716) 819-5500

(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 (see General Instruction A.2. below):

On January 11, 2012, First Niagara Bank (the “First Niagara Bank”), the wholly-owned bank subsidiary of First Niagara Financial Group, Inc., entered into an Assignment, Purchase and Assumption Agreement (the “Assignment, Purchase and Assumption Agreement”) with KeyBank N.A. (“KeyBank”), the wholly-owned bank subsidiary of KeyCorp. Upon the terms and conditions set forth in the Assignment, Purchase and Assumption Agreement, KeyBank has agreed to acquire from HSBC Bank USA, National Association and affiliates (collectively, “HSBC”), 37 branches in Upstate New York, as listed below (the “Covered HSBC Branches”), which includes assumption of $2.4 billion in deposits and the acquisition of approximately $400 million in loans (the “Acquisition”).

The Covered HSBC Branches represent a portion of the 195 branches that First Niagara Bank agreed to acquire on July 30, 2011 pursuant to a Purchase and Assumption Agreement (the “Primary Purchase Agreement”) with HSBC. The Primary Purchase Agreement permits First Niagara Bank to assign its rights and obligations to acquire a portion of the 195 branches to third party purchasers, subject to specified conditions. The Assignment, Purchase and Assumption Agreement represents an assignment with respect to the Covered HSBC Branches. The assignment of such rights and obligations with respect to branches does not alter the amount or timing of the payment or performance obligations of First Niagara Bank to HSBC under the Primary Purchase Agreement.

KeyBank has agreed to pay First Niagara Bank a deposit premium of 4.6% or approximately $110 million, based on deposit balances as of August 2011. As part of the Acquisition, KeyBank will acquire the portfolio of performing loans (primarily small business, residential mortgage and consumer loans) associated with the Covered HSBC Branches. KeyBank will also acquire the cash on hand of the Covered HSBC Branches, as well as the real and personal property of the Covered HSBC Branches and the rights of the Covered HSBC Branches under any acquired loans, leases, safe deposit agreements, relationship accounts, operating contracts or records, except for certain excluded contracts and arrangements related to the retained business of HSBC as well as HSBC intellectual property.

The Assignment, Purchase and Assumption Agreement requires KeyBank to offer employment to all employees of the Covered HSBC Branches (excluding certain employees to be retained by HSBC) on terms generally consistent with those set forth in the Primary Purchase Agreement.

The Assignment, Purchase and Assumption Agreement provides for conversion and transition services to be performed by HSBC and First Niagara Bank in connection with the transfer of the Covered HSBC Branches. As part of these services, First Niagara Bank has agreed to acquire directly from HSBC the credit card accounts and receivables associated with the Covered HSBC Branches (approximately $96.6 million as of August 2011), subject to certain conditions, and to services these credit card accounts and receivables pending KeyBank’s right to purchase them within one year following the closing.

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The scope of the assets and liabilities associated with each of the Covered HSBC Branches that will be divested through assignment to KeyBank is generally the same as the scope of the overall assets and liabilities that First Niagara Bank agreed to acquire as part of the Primary Acquisition, but limited to those at the Covered HSBC Branches. Accordingly, KeyBank will not acquire assets or liabilities related to certain business of the Covered HSBC Branches to be retained by HSBC, including the middle-market and large corporate banking business, the private banking business and the direct banking business (as well as the business of providing financial services to customers of such retained businesses). In addition, as indicated above, credit card accounts and receivables may be acquired by First Niagara Bank subject to KeyBank’s purchase right.

The Assignment, Purchase and Assumption Agreement includes representations, warranties, and covenants, indemnification, non-compete, non-solicitation and termination provisions. The Assignment, Purchase and Assumption Agreement also includes customary closing conditions and is subject to regulatory approval and to prior closing by First Niagara under the Primary Purchase Agreement. The Acquisition is anticipated to close at or about the end of the second quarter or during the third quarter of 2012.

In the event that any of the closing conditions in the Assignment, Purchase and Assumption Agreement were not to be satisfied, then unless conditions to the obligations of First Niagara Bank to close under the Primary Purchase Agreement were also not to be satisfied, First Niagara Bank would remain obligated under the Primary Purchase Agreement to acquire the HSBC Covered Branches.

The following is a list of the Covered HSBC Branches:

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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 hereunto duly authorized.

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