UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 __________________________ FORM 10-K __________________________ (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended September 30, 2023 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from _________ to __________ Commission file number 814-00237 __________________________ GLADSTONE CAPITAL CORPORAT ...