Filed pursuant to Rule 497
File No. 333-275934
Rule 482ad
September 8, 2025
Gladstone Capital Corporation Announces Proposed Convertible Notes Offering
McLean, VA, September 8, 2025: Gladstone Capital Corporation (Nasdaq: GLAD) (the “Company”) today announced the commencement of a
registered public offering of $110 million aggregate principal amount of unsecured convertible notes due 2030 (the “Notes”). In addition, the Company expects to grant the underwriter of the Notes an option to purchase up to an
additional $16.5 million in aggregate principal amount of the Notes.
The Notes will be unsecured obligations of the Company and will pay interest
semi-annually in arrears and will mature in 2030, unless earlier converted, redeemed or repurchased. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and
shares of the Company’s common stock, at the Company’s election. The interest rate, initial conversion rate, redemption or repurchase rights and other terms of the Notes will be determined at the time of pricing of the offering.
The Company intends to use the net proceeds from this offering to repay a portion of the outstanding indebtedness under its revolving credit facility and for
other general corporate purposes.
Oppenheimer & Co. Inc. is acting as sole book-running manager for this offering.
Investors are advised to carefully consider the investment objectives, risks, charges and expenses of the Company before investing. The preliminary
prospectus supplement, dated September 8, 2025, and the accompanying prospectus, dated January 17, 2024, which have been filed with the U.S. Securities and Exchange Commission (the “SEC”) contain this and other information
about the Company and should be read carefully before investing.
The proposed offering is being conducted pursuant to the Company’s effective
shelf registration statement that was initially filed with the SEC on December 7, 2023 and declared effective on January 17, 2024 (File No. 333–275934). Copies of the preliminary prospectus supplement relating to this offering
and the accompanying prospectus may be obtained, from: Oppenheimer & Co. Inc., Attention: Syndicate Prospectus Department, 85 Broad Street, 26th Floor, New York, NY 10004, by telephone at (212)
667-8055, or by email at EquityProspectus@opco.com.
This communication shall not constitute an offer to sell or
the solicitation of an offer to buy any securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the
securities laws of any such state or other jurisdiction.
About Gladstone Capital Corporation: Gladstone Capital Corporation is a publicly traded
business development company that invests in debt and equity securities consisting primarily of secured first and second lien term loans to lower middle market businesses in the United States.