Organization	6 Months Ended
Jun. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Note 1. Organization MidCap Financial Investment Corporation (the “Company,” “we,” “us,” or “our”), a Maryland corporation incorporated on February 2, 2004, is a closed-end, externally managed, diversified management investment company that has elected to be treated as a business development company (“BDC”) under the Investment Company Act of 1940, as amended (the “1940 Act”). In addition, for tax purposes we have elected to be treated as a regulated investment company (“RIC”) under Subchapter M of the Internal Revenue Code of 1986, as amended (the “Code”). We commenced operations on April 8, 2004 receiving net proceeds of $870,000 from our initial public offering by selling 62 million shares of common stock at a price of $15.00 per share (20.7 million shares at a price of $45.00 per share adjusted for the one-for-three reverse stock split). Since then, and through June 30, 2025, we have raised approximately $2,240,067 in net proceeds from additional offerings of common stock, including the Mergers with AFT and AIF (see Note 10 “Mergers with AFT and AIF” for additional information), and repurchased common stock for $254,186. On November 7, 2023, the Company entered into (i) an Agreement and Plan of Merger (the “AFT Merger Agreement”) with Apollo Senior Floating Rate Fund Inc., a Maryland corporation (“AFT”), AFT Merger Sub, Inc., a Maryland corporation and a direct wholly-owned subsidiary of the Company (“AFT Merger Sub”), and, solely for the limited purposes set forth therein, Apollo Investment Management, L.P. (the “Investment Adviser” or “AIM”), and (ii) an Agreement and Plan of Merger (the “AIF Merger Agreement” and, together with the AFT Merger Agreement, the “Merger Agreements”) with Apollo Tactical Income Fund Inc., a Maryland corporation (“AIF”), AIF Merger Sub, Inc., a Maryland corporation and a direct wholly-owned subsidiary of the Company (“AIF Merger Sub”), and, solely for the limited purposes set forth therein, the Investment Adviser. The Merger Agreements provide that, subject to the terms and conditions set forth in the applicable Merger Agreement, at the effective time of such merger, AFT and AIF will, through a two-step merger process, merge with and into the Company, with the Company continuing as the surviving company. Each of the board of directors of the Company (the “Board”), and AFT’s and AIF’s Board of Directors, including all of the respective independent directors, in each case, on the recommendation of special committees comprised solely of certain independent directors of the Company or AFT and AIF, as applicable, approved the applicable Merger Agreement and the transactions contemplated thereby. The Company's stockholders approved the necessary proposal related to the mergers of AFT and AIF with and into the Company at a special meeting of stockholders held on May 28, 2024. AFT and AIF received stockholder approval of the necessary proposals related to their previously announced mergers with and into the Company at the AFT and AIF special meetings of stockholders reconvened on June 21, 2024. On July 22, 2024, the Company completed its acquisition of AFT and AIF. For more information on the Mergers, please see Note 10 “Mergers with AFT and AIF” to our consolidated financial statements included in this report. Apollo Investment Management, L.P. is our investment adviser and an affiliate of Apollo Global Management, Inc. and its consolidated subsidiaries (“AGM”). The Investment Adviser, subject to the overall supervision of our Board, manages the day-to-day operations of and provides investment advisory services to the Company. Apollo Investment Administration, LLC (the “Administrator” or “AIA”), an affiliate of AGM, provides, among other things, administrative services and facilities for the Company. Furthermore, AIA provides on our behalf managerial assistance to those portfolio companies to which we are required to provide such assistance. Our investment objective is to generate current income and, to a lesser extent, long-term capital appreciation. We primarily invest in directly originated and privately negotiated first lien senior secured loans to privately held U.S. middle-market companies, which the Company generally defines as companies with less than $75 million in earnings before interest, taxes, depreciation and amortization (“EBITDA”), as may be adjusted for market disruptions, mergers and acquisitions-related charges and synergies, and other items. To a lesser extent, we may invest in other types of securities including first lien unitranche, second lien senior secured, unsecured, subordinated, and mezzanine loans, and equities in both private and public middle market companies.

Organization

6 Months Ended

Jun. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Note 1. Organization

MidCap Financial Investment Corporation (the “Company,” “we,” “us,” or “our”), a Maryland corporation incorporated on February 2, 2004, is a closed-end, externally managed, diversified management investment company that has elected to be treated as a business development company (“BDC”) under the Investment Company Act of 1940, as amended (the “1940 Act”). In addition, for tax purposes we have elected to be treated as a regulated investment company (“RIC”) under Subchapter M of the Internal Revenue Code of 1986, as amended (the “Code”). We commenced operations on April 8, 2004 receiving net proceeds of $870,000 from our initial public offering by selling 62 million shares of common stock at a price of $15.00 per share (20.7 million shares at a price of $45.00 per share adjusted for the one-for-three reverse stock split). Since then, and through June 30, 2025, we have raised approximately $2,240,067 in net proceeds from additional offerings of common stock, including the Mergers with AFT and AIF (see Note 10 “Mergers with AFT and AIF” for additional information), and repurchased common stock for $254,186.

On November 7, 2023, the Company entered into (i) an Agreement and Plan of Merger (the “AFT Merger Agreement”) with Apollo Senior Floating Rate Fund Inc., a Maryland corporation (“AFT”), AFT Merger Sub, Inc., a Maryland corporation and a direct wholly-owned subsidiary of the Company (“AFT Merger Sub”), and, solely for the limited purposes set forth therein, Apollo Investment Management, L.P. (the “Investment Adviser” or “AIM”), and (ii) an Agreement and Plan of Merger (the “AIF Merger Agreement” and, together with the AFT Merger Agreement, the “Merger Agreements”) with Apollo Tactical Income Fund Inc., a Maryland corporation (“AIF”), AIF Merger Sub, Inc., a Maryland corporation and a direct wholly-owned subsidiary of the Company (“AIF Merger Sub”), and, solely for the limited purposes set forth therein, the Investment Adviser. The Merger Agreements provide that, subject to the terms and conditions set forth in the applicable Merger Agreement, at the effective time of such merger, AFT and AIF will, through a two-step merger process, merge with and into the Company, with the Company continuing as the surviving company. Each of the board of directors of the Company (the “Board”), and AFT’s and AIF’s Board of Directors, including all of the respective independent directors, in each case, on the recommendation of special committees comprised solely of certain independent directors of the Company or AFT and AIF, as applicable, approved the applicable Merger Agreement and the transactions contemplated thereby. The Company's stockholders approved the necessary proposal related to the mergers of AFT and AIF with and into the Company at a special meeting of stockholders held on May 28, 2024. AFT and AIF received stockholder approval of the necessary proposals related to their previously announced mergers with and into the Company at the AFT and AIF special meetings of stockholders reconvened on June 21, 2024. On July 22, 2024, the Company completed its acquisition of AFT and AIF. For more information on the Mergers, please see Note 10 “Mergers with AFT and AIF” to our consolidated financial statements included in this report.

Apollo Investment Management, L.P. is our investment adviser and an affiliate of Apollo Global Management, Inc. and its consolidated subsidiaries (“AGM”). The Investment Adviser, subject to the overall supervision of our Board, manages the day-to-day operations of and provides investment advisory services to the Company.

Apollo Investment Administration, LLC (the “Administrator” or “AIA”), an affiliate of AGM, provides, among other things, administrative services and facilities for the Company. Furthermore, AIA provides on our behalf managerial assistance to those portfolio companies to which we are required to provide such assistance.

Our investment objective is to generate current income and, to a lesser extent, long-term capital appreciation. We primarily invest in directly originated and privately negotiated first lien senior secured loans to privately held U.S. middle-market companies, which the Company generally defines as companies with less than $75 million in earnings before interest, taxes, depreciation and amortization (“EBITDA”), as may be adjusted for market disruptions, mergers and acquisitions-related charges and synergies, and other items. To a lesser extent, we may invest in other types of securities including first lien unitranche, second lien senior secured, unsecured, subordinated, and mezzanine loans, and equities in both private and public middle market companies.