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): June 11, 2018

CAPSTAR FINANCIAL HOLDINGS, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code     (615) 732-6400

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):

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2). Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☒

On June 11, 2018, CapStar Financial Holdings, Inc., a Tennessee corporation (“CapStar”), and Athens Bancshares Corporation, a Tennessee corporation (“Athens”), issued a joint press release announcing the entry into an Agreement and Plan of Merger, dated as of June 11, 2018, by and between CapStar and Athens, pursuant to which, subject to the terms and conditions set forth therein, Athens will merge with and into CapStar (the “Merger”), with CapStar as the surviving corporation in the Merger. CapStar also announced that its Board of Directors approved the declaration of a quarterly cash dividend of $0.04 per share, on CapStar’s common stock and preferred stock, payable on or about August 15, 2018 to shareholders of record as of the close of business on July 31, 2018. A copy of the press release containing the announcement of the Merger and the declaration of the dividend is attached hereto as Exhibit 99.1 to this Report on Form 8-K and is incorporated by reference herein.

In addition, CapStar provided supplemental information regarding the proposed transaction in connection with presentations to investors. A copy of the investor presentation is attached hereto as Exhibit 99.2 to this Report on Form 8-K and is incorporated by reference herein.

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Forward Looking Statements

This communication contains “forward-looking statements” within the meaning of the federal securities laws, including Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. These forward-looking statements may include: management plans relating to the proposed transaction; the expected timing of the completion of the proposed transaction; the ability to complete the proposed transaction; the ability to obtain the required regulatory, shareholder or other approvals; any statements of the plans and objectives of management for future operations, products or services, including the execution of integration plans relating to the proposed transaction; any statements of expectation or belief; projections related to certain financial metrics or other benefits of the transaction; and any statements of assumptions underlying any of the foregoing. Forward-looking statements are typically identified by words such as “believe,” “expect,” “anticipate,” “intend,” “seek,” “plan,” “will,” “would,” “target,” “outlook,” “estimate,” “forecast,” “project” and other similar words and expressions or negatives of these words. Forward-looking statements are subject to numerous assumptions, risks and uncertainties, which change over time and are beyond CapStar’s control. Because forward-looking statements are by their nature, to different degrees, uncertain and subject to assumptions, actual results or future events could differ, possibly materially, from those that CapStar anticipated in its forward-looking statements, and future results could differ materially from historical performance. Factors that could cause or contribute to such differences include, but are not limited to, those included under Item 1A “Risk Factors” in CapStar’s Annual Report on Form 10-K for the year ended December 31, 2017 and those disclosed in CapStar’s other periodic reports filed with the Securities and Exchange Commission (the “SEC”), as well as the possibility that expected benefits of the proposed transaction may not materialize in the time frame expected or at all, or may be more costly to achieve; the proposed transaction may not be timely completed, if at all; that prior to the completion of the proposed transaction or thereafter, CapStar’s and Athens’s respective businesses may not perform as expected due to transaction-related uncertainty or other factors; that the parties are unable to successfully implement integration strategies related to the proposed transaction; that required regulatory, shareholder or other approvals are not obtained or other customary closing conditions are not satisfied in a timely manner or at all; reputational risks and the reaction of the companies’ shareholders, customers, employees or other constituents to the proposed transaction; and diversion of management time on merger-related matters. These risks, as well as other risks associated with the proposed transaction, will be more fully discussed in the joint proxy statement/prospectus that will be included in the registration statement on Form S-4 that will be filed with the SEC in connection with the proposed transaction. While the list of factors presented here is, and the list of factors presented in the registration statement on Form S-4 will be, considered representative, no such lists should be considered to be a complete statement of all potential risks and uncertainties. Unlisted factors may present significant additional obstacles to the realization of forward-looking statements. For any forward-looking statements made in this communication or in any documents, CapStar claims the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995.

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Forward-looking statements speak only as of the date they are made. CapStar does not undertake any obligation to update any forward-looking statement to reflect circumstances or events that occur after the date on which the forward-looking statement is made.

Important Additional Information and Where to Find It

In connection with the proposed merger, CapStar will file with the SEC a registration statement on Form S-4 that will include a joint proxy statement of CapStar and Athens and a prospectus of CapStar, as well as other relevant documents concerning the proposed transaction. This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval. SHAREHOLDERS OF CAPSTAR AND ATHENS ARE URGED TO READ THE REGISTRATION STATEMENT AND THE JOINT PROXY STATEMENT/PROSPECTUS REGARDING THE MERGER WHEN IT BECOMES AVAILABLE AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. When filed, this document and other documents relating to the merger filed by CapStar with the SEC can be obtained free of charge from the SEC’s website at www.sec.gov. These documents also can be obtained free of charge by accessing CapStar’s website at https://ir.capstarbank.com/ under the tab “Financials & Filings.” Alternatively, these documents, when available, can be obtained free of charge from CapStar upon written request to CapStar Financials Holding, Inc., 1201 Demonbreun Street, Suite 700, Nashville, Tennessee 37203, Attention: Investor Relations or by calling (615) 732-6455.

Participants in the Solicitation

CapStar, Athens, and certain of their respective directors, executive officers and employees may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information regarding CapStar’s directors and executive officers is available in its definitive proxy statement, which was filed with the SEC on March 19, 2018, and certain of its Current Reports on Form 8-K. Information about the directors and executive officers of Athens will be set forth in the joint proxy statement/prospectus when it is filed with the SEC. Other information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the joint proxy statement/prospectus and other relevant materials filed with the SEC. Free copies of this document may be obtained as described in the preceding paragraph.

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(d) Exhibits.

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SIGNATURE

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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