497AD

Filed pursuant to Rule 497

File No. 333-228720

Rule 482ad

[TEXT OF COMMUNICATION SENT VIA BLOOMBERG]

Gladstone Capital Corporation New Issue Announcement

Issuer:

Gladstone Capital Corporation (“GLAD”)

Security Type:

Sr. Unsecured Notes

Size:

$100mm

Format:

SEC Registered

Maturity:

January 31, 2026

Expected Rating:

A- (Egan-Jones)*

Use of Proceeds:

Redeem 6.125% Notes due ‘23, repay portion of outstanding debt under Credit Facility, fund new investment opportunities, GCP

Opt Redemption:

Make Whole Call, 3 month par call

Sole Bookrunner:

Raymond James

IPT:

5.125%

Denoms:

$2,000 x $1,000

Settlement:

T+5 (Dec 15, 2020)

Timing:

Today’s business

*Note: A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision or withdrawal at any time. Each rating agency has its own methodology for assigning ratings and, accordingly, each rating should be evaluated independently of any other rating.

Investors are advised to carefully consider the investment objective, risks, charges and expenses of GLAD before investing. The preliminary prospectus supplement dated Dec 8, 2020, together with an accompanying prospectus, which have been filed with the Securities and Exchange Commission, contain this and other information about GLAD and should be read carefully before investing. The information in the preliminary prospectus supplement and the accompanying prospectus, and in this announcement is not complete and may be changed.

The preliminary prospectus supplement, the accompanying prospectus and this announcement do not constitute offers to sell or the solicitation of offers to buy nor will there be any sale of the securities referred to in this announcement in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of such state or jurisdiction.

A SHELF REGISTRATION STATEMENT RELATING TO THESE SECURITIES IS ON FILE WITH AND HAS BEEN DECLARED EFFECTIVE BY THE U.S. SECURITIES AND EXCHANGE COMMISSION (SEC). THE OFFERING MAY BE MADE ONLY BY MEANS OF A PROSPECTUS SUPPLEMENT AND AN ACCOMPANYING PROSPECTUS. YOU MAY GET THESE DOCUMENTS, AS WELL AS THE FINAL PROSPECTUS, PROSPECTUS SUPPLEMENT OR PRICING SUPPLEMENT (WHEN COMPLETED), AS APPLICABLE (SUCH PRELIMINARY AND FINAL DOCUMENTATION TOGETHER THE OFFERING DOCUMENTATION) FOR FREE BY SEARCHING THE SEC ONLINE DATABASE AT: WWW.SEC.GOV. ALTERNATIVELY, YOU MAY OBTAIN A COPY OF THE OFFERING DOCUMENTATION FROM RAYMOND JAMES & ASSOCIATES, INC., 880 CARILLON PARKWAY, ST. PETERSBURG, FLORIDA 33716.