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: November 19, 2018

(Date of earliest event reported)

WhiteHorse Finance, Inc.

(Exact name of registrant as specified in its charter)

(305) 381-6999

(Registrant’s telephone number, including area code)

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:

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

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.  ¨

Item 1.01. Entry into a Material Definitive Agreement

On November 19, 2018, WhiteHorse Finance Credit I, LLC (“WhiteHorse Credit”), a wholly owned subsidiary of WhiteHorse Finance, Inc. (the “Company”), entered into an amendment (the “First Amendment”) to the third amended and restated loan agreement (the “Third Amended and Restated Loan Agreement”), dated May 15, 2018, by and among WhiteHorse Credit, as borrower, JPMorgan Chase Bank, National Association, as administrative agent and lender, the financial providers thereto, and the Company, as portfolio manager. Among other things, the First Amendment allows for an increased advance rate, a temporary reduction in the minimum funding amount, and a decrease in the concentration of second lien loans. The First Amendment also allows the Company to reduce its outstanding debt under the facility with the cash raised from the recent public offering of $35,000,000 aggregate principal amount of 6.50% notes due 2025.

The description above is only a summary of the First Amendment and is qualified in its entirety by reference to a copy of the First Amendment, which is filed as Exhibit 10.1 to this current report on Form 8-K.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

The information in Item 1.01 of this current report on Form 8-K is incorporated by reference into this Item 2.03.

Item 7.01. Regulation FD Disclosure

On November 20, 2018, the Company issued a press release announcing the execution of the First Amendment. Such press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

The information in Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1 furnished herewith, is being furnished and shall not be deemed “filed” for any purpose of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such Section. The information in Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1 furnished herewith, shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Forward-Looking Statements

This Current Report on Form 8-K, including Exhibit 99.1 furnished herewith, may contain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Statements other than statements of historical facts included in this Current Report on Form 8-K may constitute forward-looking statements and are not guarantees of future performance or results and involve a number of risks and uncertainties. Actual results may differ materially from those in the forward-looking statements as a result of a number of factors, including those described from time to time in filings with the Securities and Exchange Commission. The Company undertakes no duty to update any forward-looking statement made herein. All forward-looking statements speak only as of the date of this Current Report on Form 8-K.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits

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.