UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 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): August 11, 2023 (August 10, 2023)

Gladstone Capital Corporation

(Exact name of registrant as specified in its charter)

(703) 287-5800

(Registrant’s telephone number, including area code)

(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:

Securities registered pursuant to Section 12(b) of the Act:

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 August 10, 2023, Gladstone Capital Corporation (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) by and among the Company, Gladstone Management Corporation, Gladstone Administration, LLC and Piper Sandler & Co., as representative of the several underwriters named therein, in connection with the issuance and sale of $50.0 million aggregate principal amount of the Company’s 7.75% Notes due 2028 (the “Offering”). The Company has also granted the underwriters a 30-day option to purchase up to an additional $7,500,000 aggregate principal amount of the 7.75% Notes due 2028 to cover overallotments, if any. The closing of the Offering is expected to occur on August 17, 2023, subject to customary closing conditions.

The Offering was made pursuant to the Company’s effective shelf registration statement on Form N-2 (Registration No. 333–261398) previously filed with the Securities and Exchange Commission, as supplemented by a preliminary prospectus supplement dated August 10, 2023, the pricing term sheet dated August 10, 2023 and a final prospectus supplement dated August 10, 2023. This Current Report on Form 8-K shall not constitute an offer to sell or a solicitation of an offer to buy any securities, nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or other jurisdiction.

The description above is only a summary of the material provisions of the Underwriting Agreement and is qualified in its entirety by reference to a copy of the Underwriting Agreement, which is filed as Exhibit 1.1 to this Current Report on Form 8-K and incorporated by reference herein.

(d) Exhibits.

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.