v3.26.1
Document and Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2025
Mar. 25, 2026
Cover [Abstract]    
Document Type 10-K  
Amendment Flag false  
Document Period End Date Dec. 31, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus FY  
Document Transition Report false  
Entity Registrant Name MSD Investment Corp.  
No Trading Symbol Flag true  
Entity Central Index Key 0001849894  
Current Fiscal Year End Date --12-31  
Securities Act File Number 814-01481  
Entity Incorporation, State or Country Code MD  
Entity Tax Identification Number 87-4195402  
Entity Address, Address Line One 550 Madison Ave  
Entity Address, Address Line Two 20th Floor  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10022  
City Area Code 212  
Local Phone Number 303-4728  
Title of 12(b) Security None  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   138,244,276
Document Annual Report true  
Entity Well-known Seasoned Issuer No  
Entity Voluntary Filers No  
Document Financial Statement Error Correction [Flag] false  
Entity Public Float   $ 0
Auditor Name Deloitte & Touche LLP  
Auditor Location New York, New York  
Auditor Firm ID 34  
Documents Incorporated by Reference

Documents Incorporated by Reference

Portions of the registrant’s definitive proxy statement relating to the registrant’s 2026 annual meeting of shareholders (the “2026 Proxy Statement”), to be filed with the Securities and Exchange Commission within 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K are incorporated by reference into Part III of this Form 10-K as indicated herein.

  
Auditor Opinion [Text Block]

Opinion on the Consolidated Financial Statements and Consolidated Financial Highlights

We have audited the accompanying consolidated statements of assets and liabilities of MSD Investment Corp. and subsidiaries (the "Company"), including the consolidated schedules of investments, as of December 31, 2025 and 2024, the related consolidated statements of operations, changes in net assets, and cash flows for each of the three years in the period then ended, and the consolidated financial highlights (in Note 12) for each of the four years in the period then ended and for the period from December 21, 2021 (commencement of operations) to December 31, 2021, and the related notes (collectively referred to as the “financial statements and financial highlights”). In our opinion, the financial statements and financial highlights present fairly, in all material respects, the consolidated financial position of the Company as of December 31, 2025 and 2024, and the results of its operations, changes in its net assets, and its cash flows for each of the three years in the period then ended, and the financial highlights for each of the four years in the period then ended and for the period from December 21, 2021 (commencement of operations) to December 31, 2021, in conformity with accounting principles generally accepted in the United States of America.