Organization	12 Months Ended
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Note 1. Organization MidCap Financial Investment Corporation (the “Company”, “MFIC”, “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 (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 December 31, 2023, we have raised approximately $2,240,067 in net proceeds from additional offerings of common stock and repurchased common stock for $248,107. On August 1, 2022, the Company changed its name from “Apollo Investment Corporation” to “MidCap Financial Investment Corporation”. Our common stock began to trade under the ticker “MFIC” on the NASDAQ Global Stock Market on August 12, 2022. On November 3, 2022, the Company's Board changed the Company’s fiscal year end from March 31 to December 31, effective December 31, 2022. See Note 3 to the consolidated financial statements for further information. 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, the Adviser, 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 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 Company’s Board of Directors, 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, have approved the applicable Merger Agreement and the transactions contemplated thereby. Consummation of the Mergers, which is currently anticipated to occur in the first half of 2024, is subject to certain closing conditions, including requisite approvals of the Company’s, AFT’s and AIF’s stockholders and certain other closing conditions. For more information on the Mergers, please see “Management’s Discussion and Analysis of Financial Condition and Results of Operations - Recent Developments.” Apollo Investment Management, L.P. (the “Investment Adviser” or “AIM”) 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 of Directors, 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 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

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Note 1. Organization

MidCap Financial Investment Corporation (the “Company”, “MFIC”, “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 (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 December 31, 2023, we have raised approximately $2,240,067 in net proceeds from additional offerings of common stock and repurchased common stock for $248,107.

On August 1, 2022, the Company changed its name from “Apollo Investment Corporation” to “MidCap Financial Investment Corporation”. Our common stock began to trade under the ticker “MFIC” on the NASDAQ Global Stock Market on August 12, 2022.

On November 3, 2022, the Company's Board changed the Company’s fiscal year end from March 31 to December 31, effective December 31, 2022. See Note 3 to the consolidated financial statements for further information.

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, the Adviser, 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 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 Company’s Board of Directors, 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, have approved the applicable Merger Agreement and the transactions contemplated thereby. Consummation of the Mergers, which is currently anticipated to occur in the first half of 2024, is subject to certain closing conditions, including requisite approvals of the Company’s, AFT’s and AIF’s stockholders and certain other closing conditions. For more information on the Mergers, please see “Management’s Discussion and Analysis of Financial Condition and Results of Operations - Recent Developments.”

Apollo Investment Management, L.P. (the “Investment Adviser” or “AIM”) 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 of Directors, 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 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.