Main Street Capital美股招股说明书(2025-08-14版)

We are offering $350,000,000 in aggregate principal amount of 5.400% notes due 2028, which we refer to as the Notes. The Notes will mature on August15,2028. We will pay interest on the Notes on February 15 and August 15 of each year, beginning on February15, 2026. We may redeem the Notes in whole or in part at any time or from time to time, at the redemption price set forth under the caption “Description of the Notes —Optional Redemption” in this prospectus supplement. In addition, holders of the Notes can require us to repurchase some or all of the Notes at a purchase price equal to100% of their principal amount, plus accrued and unpaid interest to, but not including, the repurchase date upon the occurrence of a “Change of Control RepurchaseEvent” (as defined herein). The Notes will be issued in minimum denominations of $2,000 and integral multiples of $1,000 in excess thereof. The Notes will be our direct unsecured obligations and rankpari passuwith our existing and future unsecured indebtedness but will rank senior to our futureindebtedness that is expressly subordinated in right of payment to the Notes issued by Main Street Capital Corporation. See “Summary of the Offering — Ranking ofNotes.” The securities in which we invest generally would be rated below investment grade if they were rated by rating agencies. Below investment gradesecurities, which are often referred to as “junk,” have predominantly speculative characteristics with respect to the issuer’s capacity to pay interest and repayprincipal. They may also be difficult to value and are illiquid.We are an internally managed, closed-end, non-diversified management investment company that has elected to be treated as a business development company under the Investment Company Act of 1940, as amended. Our principal investment objective is to maximize our investment portfolio’s total return by generating currentincome from our debt investments and current income and capital appreciation from our equity and equity-related investments, including warrants, convertible securitiesand other rights to acquire equity securities in a portfolio company. Investing in the Notes involves a high degree of risk and should be considered highly speculative. Before investing in the Notes, you should reviewcarefully the risks and uncertainties, including the risk of leverage, described in the sections titled “Supplementary Risk Factors” beginning on pageS-10ofthis prospectus supplement, “Risk Factors” beginning on page12of the accompanying prospectus and in our most recently filed Annual Report on Form 10-Kand subsequent filings with the Securities and Exchange Commission, or SEC, as well as under similar headings in the other documents that are filed on orafter the date hereof and incorporated by reference into this prospectus supplement and the accompanying prospectus. This prospectus supplement and the accompanying prospectus contain important information about us that a prospective investor should know before investing inthe Notes. We may also authorize one or more free writing prospectuses to be provided to you in connection with this offering. You should carefully read this prospectussupplement, the accompanying prospectus, and any related free writing prospectus, and any information incorporated by reference in each, before investing in the Notesand keep them for future reference. We file annual, quarterly and current reports, proxy statements and other information with the SEC. This information is availablefree of charge by contacting us at 1300 Post Oak Boulevard, 8th Floor, Houston, Texas 77056 or by telephone at (713) 350-6000 or on our website atwww.mainstcapital.com. Information contained on our website is not incorporated by reference into this prospectus supplement or the accompanying prospectus, andyou should not consider that information to be part of this prospectus supplement or the accompanying prospectus. The SEC also maintains a website atwww.sec.govthat contains such information.Neither the SEC nor any state securities commission, nor any other regulatory body, has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense. Per NoteTotalPublic offering price99.989%$349,961,500Underwriting discount (sales load)0.450%$1,575,000Proceeds to Main Street Capital Corporation (before estimated expenses of $650,000)99.539%$348,386,500 The public offering price set forth above does not include accrued interest, if any. Interest on the Notes will accrue from August15, 2025 and must be paid by thepurchaser if the Notes are delivered after August15, 2025. THE NOTES ARE NOT DEPOSITS OR OTHER OBLIGATIONS OF A BANK AND ARE NOT INSURED BY THE FEDERAL DEPOSITINSURANCE CORPORATION OR ANY OTHER GOVERNMENT AGENCY. Delivery of the Notes in book-entry form only through The Depository Trust Company will be made on or a