Horizon Technology Finance Corp美股招股说明书(2026-03-06版)

HORIZON TECHNOLOGY FINANCE CORPORATIONMONROE CAPITAL CORPORATIONSupplement No. 1, dated March 5, 2026, to theJoint Proxy Statement/Prospectus, dated January 16, 2026 This supplement contains information that amends, supplements or modifies certain information contained in the combinedprospectus of Horizon Technology Finance Corporation (“HRZN”), and definitive joint proxy statement of HRZN and Monroe CapitalCorporation (“MRCC”), dated January 16, 2026 (the “Joint Proxy Statement/Prospectus”). This supplement is part of, and should beread in conjunction with, the Joint Proxy Statement/Prospectus. The Joint Proxy Statement/Prospectus has been filed with the U.S.Securities and Exchange Commission (the “SEC”), and is available free of charge at www.sec.gov or by calling HRZN at (860) 676-8654, or by writing to HRZN at 312 Farmington Avenue, Farmington, Connecticut 06032, Attention: Investor Relations, or by callingMRCC at (312) 258-8300, or by writing to MRCC at 155 North Wacker Drive, 35th Floor, Chicago, Illinois 60606, Attention: InvestorRelations. Capitalized terms used herein but not defined shall have the meanings ascribed to such terms in the Joint ProxyStatement/Prospectus. INCORPORATION BY REFERENCE FOR HRZN This supplement incorporates by reference the documents set forth below that have previously been filed with the SEC: •HRZN’s Annual Report on Form 10-K for the period ended December 31, 2025, filed with the SEC onMarch 3, 2026; and•HRZN’s Current Report on Form 8-K (other than information furnished rather than filed) filed with the SEC onFebruary 11,2026. INCORPORATION BY REFERENCE FOR MRCC This supplement incorporates by reference the documents set forth below that have previously been filed with the SEC: •MRCC’s Annual Report on Form 10-K for the period ended December 31, 2025, filed with the SEC onMarch 5, 2026; and•MRCC’s Current Report on Form 8-K (other than information furnished rather than filed) filed with the SEC onJanuary 15,2026.