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) February 10, 2015

ESB Financial Corporation

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code (724) 758-5584

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 (see General Instruction A.2 below):

Effective February 10, 2015, Wesbanco, Inc. (“WesBanco”) completed its previously announced merger with ESB Financial Corporation (“ESB”). Pursuant to the Agreement and Plan of Merger, dated as of October 29, 2014, by and among WesBanco, Wesbanco Bank, Inc., a wholly-owned subsidiary of WesBanco (“WesBanco Bank”), ESB and ESB Bank, a Pennsylvania state-chartered stock savings bank and a wholly-owned subsidiary of ESB (“ESB Bank”) (the “Merger Agreement”), ESB was merged with and into WesBanco, with WesBanco continuing as the surviving corporation (the “Merger”). As a result of the Merger, each outstanding share of ESB common stock, par value $0.01 (other than shares held by ESB or WesBanco), was converted into the right to receive (i) 0.502 of a share of WesBanco common stock, par value $2.0833 per share and (ii) $1.76 in cash, without interest (the “Merger Consideration”).

Immediately following the completion of the Merger, ESB Bank was merged with and into WesBanco Bank, with WesBanco Bank surviving the merger.

Additional information and details of the Merger and the Merger Agreement were previously disclosed in the joint proxy statement/prospectus filed by WesBanco with the Securities and Exchange Commission (the “SEC”) on December 11, 2014 (SEC File No. 333-200391) (the “Joint Proxy Statement/Prospectus”). Any description of the Merger Agreement is qualified in its entirety by reference to the complete copy of the Merger Agreement which is included as Annex A in the Joint Proxy Statement/Prospectus and as Exhibit 2.1 hereto and is incorporated by reference herein.

The information disclosed in Item 2.01 of this Current Report on Form 8-K is hereby incorporated by reference.

In connection with the consummation of the Merger, ESB notified the Nasdaq Global Market (“Nasdaq”) that, as of the effective time of the Merger, ESB would be merged with and into WesBanco and each of the shares of ESB common stock outstanding immediately prior to the effective time of the Merger (other than those to be cancelled in accordance with the Merger Agreement) would be converted into and become exchangeable for the right to receive the Merger Consideration, and requested that Nasdaq file with the SEC a notification of removal from listing on Form 25 to report that shares of ESB’s common stock are no longer listed on Nasdaq.

As the effective time of the Merger, ESB’s shareholders ceased to have any rights as shareholders of ESB and were entitled only to receive the Merger Consideration.

As of the effective time of the Merger, WesBanco completed its acquisition of ESB in accordance with the Merger Agreement. In addition, immediately following consummation of the Merger, ESB Bank was merged with and into WesBanco Bank, with WesBanco Bank surviving the merger.

As previously disclosed, on October 29, 2014, ESB entered into the Merger Agreement. On January 22, 2015, the Merger Agreement was approved by the shareholders of ESB at a special meeting of shareholders.

The disclosures under Items 2.01, 3.01 and 3.03 above are incorporated herein by reference.

(e) In connection with the Merger, the Board of Directors of ESB approved and entered into a Separation Agreement among ESB, ESB Bank, Wesbanco and Wesbanco Bank and Richard E. Canonge, Senior Vice President of ESB (in addition to the Separation Agreements previously entered into with the President and the Group Senior Vice Presidents of ESB at the time the Merger Agreement was signed). The Separation Agreement specifies the amount of cash severance to be paid to the executive upon completion of the Merger, and provides for the release of claims against ESB, Wesbanco and their subsidiaries, affiliates, directors, officers, employees and others.

On February 10, 2015, WesBanco and ESB issued a joint press release announcing the consummation of the Merger. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

The following exhibits are included herewith.

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.