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: July 13, 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. ¨

On July 13, 2018, WhiteHorse Finance, Inc. (the “Company”) entered into a Note Purchase Agreement (the “Note Purchase Agreement”) governing the issuance of $30,000,000 in aggregate principal amount of senior unsecured notes (the “Notes”) to qualified institutional investors in a private placement. The Notes have a fixed interest rate of 6.00% and are due on August 7, 2023, unless redeemed, purchased or prepaid prior to such date by the Company or its affiliates in accordance with their terms. Interest on the Notes will be due semiannually. This interest rate is subject to increase (up to 6.50%) in the event that, subject to certain exceptions, the Notes cease to have an investment grade rating. In addition, the Company is obligated to offer to repay the Notes at par if certain change in control events occur. The Notes are general unsecured obligations of the Company that rank pari passu with all outstanding and future unsecured unsubordinated indebtedness issued by the Company.

The closing of the transaction is subject to customary closing conditions, and the Notes are expected to be delivered and paid for on August 7, 2018. The Company intends to use the net proceeds from this offering, together with cash on hand, to redeem all of its 6.50% Senior Notes due 2020.

The Note Purchase Agreement contains customary terms and conditions for senior unsecured notes issued in a private placement, including, without limitation, affirmative and negative covenants such as information reporting, maintenance of the Company’s status as a business development company within the meaning of the Investment Company Act of 1940, as amended, and a regulated investment company under the Internal Revenue Code of 1986, as amended, minimum shareholders’ equity, minimum asset coverage ratio, maximum debt to equity ratio and prohibitions on certain fundamental changes of the Company or any subsidiary guarantor. The Note Purchase Agreement also contains customary events of default with customary cure and notice periods, including, without limitation, nonpayment, incorrect representation in any material respect, breach of covenant, cross-default under other indebtedness of the Company or certain significant subsidiaries, certain judgements and orders, and certain events of bankruptcy.

The Notes were offered in reliance on Section 4(a)(2) of Securities Act of 1933, as amended (the “Securities Act”). The Notes have not and will not be registered under the Securities Act or any state securities laws and, unless so registered, may not be offered or sold in the United States except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act, as applicable.

The information on this Current Report on Form 8-K shall not constitute an offer to sell or a solicitation of an offer to purchase the Notes or any other securities, and shall not constitute an offer, solicitation or sale in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful.

The description above is only a summary of the material provisions of the Note Purchase Agreement and is qualified in its entirety by reference to the copy of the Note Purchase Agreement which is filed as Exhibit 10.1 to this current report on Form 8-K and is incorporated herein by reference thereto.

The Company issued a press release on July 17, 2018 to announce the signing of the Note Purchase Agreement, a copy of which is attached hereto as Exhibit 99.1.

The disclosure set forth above under Item 1.01 is incorporated by reference herein.

(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.