MSC INCOME FUND, INC.

Notes to the Consolidated Financial Statements

NOTE A —ORGANIZATION AND BASIS OF PRESENTATION

1. Organization

MSC Income Fund, Inc. (“MSIF” or, together with its consolidated subsidiaries, “MSC Income” or the “Fund”) is a principal investment firm primarily focused on providing debt capital to private (“Private Loan”) companies owned by or in the process of being acquired by a private equity fund (its “Private Loan investment strategy”). MSC Income’s portfolio investments are typically made to support leveraged buyouts, recapitalizations, growth financings, refinancings and acquisitions of companies that operate in diverse industry sectors. MSC Income seeks to partner with private equity fund sponsors in its Private Loan investment strategy and primarily invests in secured debt investments of Private Loan companies generally headquartered in the United States.

MSC Income also maintains a portfolio of customized long-term debt and equity investments in lower middle market (“LMM”) companies (its “LMM investment portfolio”), and through those investments MSC Income has partnered with entrepreneurs, business owners and management teams in co-investments with Main Street Capital Corporation (“Main Street”), a New York Stock Exchange (“NYSE”) listed business development company (“BDC”), utilizing the customized “one-stop” debt and equity financing solutions provided in Main Street’s LMM investment strategy (the “LMM investment strategy”). Through the LMM investment strategy, MSC Income primarily invested in secured debt investments, equity investments, warrants and other securities of LMM companies typically based in the United States. Effective upon the MSC Income Listing (as defined below) on January 29, 2025, MSC Income changed its investment strategy for investments in new portfolio companies to be solely focused on its Private Loan investment strategy, rather than its historical focus primarily on the Private Loan investment strategy and secondarily on the LMM investment strategy (as further discussed below).

MSC Income also maintains a legacy portfolio of investments in larger middle market (“Middle Market”) companies (its “Middle Market investment portfolio”) and a limited portfolio of other portfolio (“Other Portfolio”) investments. MSC Income’s Middle Market investments are generally debt investments in companies owned by a private equity fund that were originally issued through a syndication financing process. MSC Income has generally stopped making new Middle Market investments and expects the size of its Middle Market investment portfolio to continue to decline in future periods as its existing Middle Market investments are repaid or sold. MSC Income’s Other Portfolio investments primarily consist of investments that are not consistent with the typical profiles for its Private Loan, LMM or Middle Market portfolio investments, including investments in unaffiliated investment companies and private funds managed by third parties. Similar to its Middle Market investments, MSC Income has generally stopped making new Other Portfolio investments and expects the size of its Other Portfolio to continue to decline in future periods as its existing Other Portfolio investments are repaid or sold.

The “Investment Portfolio,” as used herein, refers to all of MSC Income’s investments in Private Loan portfolio companies, investments in LMM portfolio companies, investments in Middle Market portfolio companies and Other Portfolio investments.

MSIF was formed in November 2011 to operate as an externally managed BDC under the Investment Company Act of 1940, as amended (the “1940 Act”). MSIF has elected to be treated for U.S. federal income tax purposes as a regulated investment company (“RIC”) under Subchapter M of the Internal Revenue Code of 1986, as amended (the “Code”). As a result, MSIF generally does not pay corporate-level U.S. federal income taxes on any net ordinary taxable income or capital gains that it distributes to its stockholders.

On October 28, 2020, MSC Income’s stockholders approved the appointment of MSC Adviser I, LLC (the “Adviser”), which is wholly-owned by Main Street, as MSC Income’s investment adviser and administrator under an Investment Advisory and Administrative Services Agreement dated October 30, 2020 (the “Prior Investment Advisory Agreement”).

On January 29, 2025, MSC Income’s shares of common stock were listed on the NYSE under the ticker symbol “MSIF” (the “MSC Income Listing”).

On January 29, 2025, in connection with the MSC Income Listing, MSC Income entered into an Amended and Restated Investment Advisory and Administrative Services Agreement (the “Advisory Agreement”) with the Adviser. The Advisory Agreement was approved by the affirmative vote of the holders of a majority of MSC Income’s outstanding voting securities, as defined in the 1940 Act, at a special meeting of MSC Income’s stockholders held on December 11, 2024 (the “2024 Special Meeting”), and the Advisory Agreement became effective upon the MSC Income Listing. In such role, the Adviser has the responsibility to manage the business of MSC Income, including the responsibility to identify, evaluate, negotiate and structure prospective investments, make investment and portfolio management decisions, monitor its Investment Portfolio and provide ongoing administrative services.

On January 29, 2025, in connection with the MSC Income Listing, the Fund amended and restated its Articles of Amendment and Restatement, as amended, by filing new Articles of Amendment and Restatement of the Fund (the “New Articles”) with the State Department of Assessments and Taxation of the State of Maryland. The New Articles revised the Fund’s charter to, among other things, (i) include a provision that limits the transferability of shares of its common stock outstanding at the time of the MSC Income Listing during the 365-day period following the MSC Income Listing, (ii) reflect an amendment to delete provisions regarding restrictions and requirements applicable to its dividend reinvestment plan, (iii) reflect an amendment to delete provisions prohibiting acquisitions of assets in exchange for shares of its common stock and restricting certain transactions between the Fund and the Adviser and its affiliates and (iv) delete certain provisions required by, and remove references to, the NASAA Guidelines in order to conform certain provisions of the Fund’s charter more closely to provisions in the charters of other BDCs whose securities are listed and publicly-traded on a national securities exchange.

On January 30, 2025, in connection with the MSC Income Listing, MSC Income closed a follow-on public offering of 5,500,000 shares of its common stock, at the public offering price of $15.53 per share. In addition, on February 3, 2025, MSC Income issued and sold 825,000 additional shares of its common stock, at the public offering price of $15.53 per share, pursuant to the underwriters’ full exercise of their overallotment option (together with the offering and sale of the 5,500,000 shares, the “MSC Income Offering”). Net of underwriting discounts and commissions and offering costs, the Fund received net cash proceeds of $90.5 million in connection with the MSC Income Offering.

MSIF has certain direct and indirect wholly-owned subsidiaries that have elected to be taxable entities (the “Taxable Subsidiaries”). The primary purpose of the Taxable Subsidiaries is to permit MSIF to hold equity investments in portfolio companies which are “pass-through” entities for tax purposes. MSIF also has certain direct and indirect wholly-owned subsidiaries formed for financing purposes (the “Structured Subsidiaries”).

Unless otherwise noted or the context otherwise indicates, the terms “MSC Income” and the “Fund” refer to MSIF and its consolidated subsidiaries, which include the Taxable Subsidiaries and the Structured Subsidiaries.

2. Basis of Presentation

MSC Income’s consolidated financial statements are prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”). The Fund is an investment company following accounting and reporting guidance in Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 946, Financial Services—Investment Companies (“ASC 946”). For each of the periods presented herein, MSC Income’s consolidated financial statements include the accounts of MSIF and its consolidated subsidiaries. MSC Income’s results of operations for the three and nine months ended September 30, 2025 and 2024, cash flows for the nine months ended September 30, 2025 and 2024 and financial position as of September 30, 2025 and December 31, 2024 are presented on a consolidated basis. The effects of all intercompany transactions between MSIF and its consolidated subsidiaries have been eliminated in consolidation.

The accompanying unaudited consolidated financial statements of MSC Income are presented in conformity with U.S. GAAP for interim financial information and pursuant to the requirements for reporting on Form 10-Q and Articles 6, 10 and 12 of Regulation S-X. Accordingly, certain disclosures accompanying annual consolidated financial statements prepared in accordance with U.S. GAAP are omitted. The unaudited consolidated financial statements and notes should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2024. In the opinion of management, the unaudited consolidated financial results included herein contain all adjustments, consisting solely of normal recurring accruals, considered necessary for the fair presentation of financial statements for the interim periods included herein. The results of operations for the three and nine months ended September 30, 2025 are not necessarily indicative of the operating results to be expected for the full year. Financial statements prepared on a U.S. GAAP basis require management to make estimates and assumptions that affect the amounts and disclosures reported in the consolidated financial statements and accompanying notes. Such estimates and assumptions could change in the future as more information becomes known, which could impact the amounts reported and disclosed herein.

Principles of Consolidation

Under ASC 946, MSC Income is precluded from consolidating other entities in which MSC Income has equity investments, including those in which it has a controlling interest, unless the other entity is another investment company. An exception to this general principle in ASC 946 occurs if MSC Income holds a controlling interest in an operating company that provides all or substantially all of its services directly to MSC Income. Accordingly, as noted above, MSC Income’s consolidated financial statements include the financial position and operating results for the Taxable Subsidiaries and the Structured Subsidiaries. MSC Income has determined that none of its portfolio investments qualify for this exception. Therefore, MSC Income’s Investment Portfolio is carried on the Consolidated Balance Sheets at fair value, as discussed further in Note B.1. — Summary of Significant Accounting Policies — Valuation of the Investment Portfolio, with any adjustments to fair value recognized as “Net Unrealized Appreciation (Depreciation)” until the investment is realized, usually upon exit, resulting in any gain or loss being recognized as a “Net Realized Gain (Loss),” in both cases on the Consolidated Statements of Operations.

Portfolio Investment Classification

MSC Income classifies its Investment Portfolio in accordance with the requirements of the 1940 Act. Under the 1940 Act, (a) “Control” investments are defined as investments in which MSC Income owns more than 25% of the voting securities or has rights to maintain greater than 50% of the board representation, (b) “Affiliate” investments are defined as investments in which MSC Income owns between 5% and 25% (inclusive) of the voting securities and does not have rights to maintain greater than 50% of the board representation and (c) “Non-Control/Non-Affiliate” investments are defined as investments that are neither Control investments nor Affiliate investments. For purposes of determining the classification of its Investment Portfolio, MSC Income has excluded consideration of any voting securities or board appointment rights held by Main Street or any other advisory client of the Adviser.

3. Reverse Stock Split

On December 16, 2024, in advance of the MSC Income Listing, the Fund effectuated a two-for-one reverse stock split of its outstanding common stock pursuant to approval from its Board of Directors (the “Reverse Stock Split”). As a result of the Reverse Stock Split, every two shares of the Fund’s issued and outstanding common stock were converted into one share of issued and outstanding common stock, without any change in the par value or shares authorized. All share, per share, common stock and additional paid-in capital amounts presented in these consolidated financial statements and notes to the consolidated financial statements prior to December 16, 2024 have been retrospectively adjusted to give effect to the Reverse Stock Split.

4. Revisions to the Presentation of Previously Issued Financial Statements

As of June 30, 2025, MSC Income changed its tax presentation on the Consolidated Statement of Operations to voluntarily correct an immaterial error in order to comply with the applicable presentation requirements in 210.6-07 of Regulation S-X. Net investment income now includes excise tax expense and net investment income related federal and state income and other tax expenses. These revisions had no impact on net increase in net assets resulting from operations or net increase in net assets resulting from operations per share. All prior period net investment income and net investment income per share amounts presented in these consolidated financial statements and the notes thereto have been retrospectively adjusted to conform to the current presentation. The impact of the adjustments on the Consolidated Statement of Operations for the three and nine months ended September 30, 2024 is as follows:

The adjustments also impacted the ratio of net investment income to average net asset value (“NAV”) as presented in Note E — Financial Highlights.

NOTE B —SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

1. Valuation of the Investment Portfolio

MSC Income accounts for its Investment Portfolio at fair value. As a result, MSC Income follows the provisions of ASC 820, Fair Value Measurements and Disclosures (“ASC 820”). ASC 820 defines fair value, establishes a framework for measuring fair value, establishes a fair value hierarchy based on the quality of inputs used to measure fair value and enhances disclosure requirements for fair value measurements. ASC 820 requires MSC Income to assume that the portfolio investment is to be sold in the principal market to independent market participants, which may be a hypothetical market. Market participants are defined as buyers and sellers in the principal market that are independent, knowledgeable and willing and able to transact.

MSC Income’s portfolio strategy calls for it to invest primarily in debt securities issued by Private Loan companies. MSC Income also maintains its LMM investment portfolio and its portfolio strategy calls for it to invest in future follow-on investments in illiquid debt and equity securities issued by its existing LMM portfolio companies, as or if such opportunities exist. Effective on the date of the MSC Income Listing, the Fund has changed its investment strategy with respect to new platform investments to be solely focused on the Private Loan investment strategy. As a result, the size of the LMM investment portfolio is expected to decrease over time as existing LMM investments are repaid or sold in the ordinary course of business. MSC Income also maintains a legacy portfolio of investments in Middle Market companies and a limited portfolio of Other Portfolio investments which are also expected to decrease over time as MSC Income is generally no longer making new Middle Market investments or Other Portfolio investments. MSC Income’s portfolio investments may be subject to restrictions on resale.

Private Loan investments may include investments which have no established market or have established markets that are not active, while LMM investments and Other Portfolio investments generally have no established trading market. Middle Market portfolio investments generally have established markets that are not active. MSC Income determines in good faith the fair value of its Investment Portfolio pursuant to a valuation policy in accordance with ASC 820, with such valuation process approved by its Board of Directors and in accordance with the 1940 Act. MSC Income’s valuation policies and processes are intended to provide a consistent basis for determining the fair value of MSC Income’s Investment Portfolio.

For Private Loan and Middle Market portfolio investments in debt securities for which it has determined that third-party quotes or other independent pricing are not available or appropriate, MSC Income generally estimates the fair value based on the assumptions that it believes hypothetical market participants would use to value the investment in a current hypothetical sale using the yield-to-maturity model (“Yield-to-Maturity”) valuation method. For LMM portfolio investments, MSC Income generally reviews external events, including private mergers, sales and acquisitions involving comparable companies, and includes these events in the valuation process by using an enterprise value waterfall methodology (“Waterfall”) for its LMM equity investments and an income approach using a Yield-to-Maturity valuation method for its LMM debt investments. For Middle Market portfolio investments in debt securities for which it has determined that third-party quotes or other independent prices are available, MSC Income primarily uses quoted prices in the valuation process. MSC Income determines the appropriateness of the use of third-party broker quotes, if any, in determining fair value based on its understanding of the level of actual transactions used by the broker to develop the quote and whether the quote was an indicative price or binding offer, the depth and consistency of broker quotes and the correlation of changes in broker quotes with underlying performance of the portfolio company and other market indices. For its Other Portfolio equity investments, MSC Income generally calculates the fair value of the investment primarily based on the NAV of the investment fund and adjusts the fair value for other factors deemed relevant that would affect the fair value of the investment. All of the valuation approaches for MSC Income’s portfolio investments estimate the value of the investment as if MSC Income were to sell, or exit, the investment as of the measurement date.

These valuation approaches consider the value associated with MSC Income’s ability to control the capital structure of the portfolio company, as well as the timing of a potential exit. For valuation purposes, “control” portfolio investments are composed of debt and equity securities in companies for which MSC Income has a controlling interest in the equity ownership of the portfolio company or the ability to nominate a majority of the portfolio company’s board of directors. For valuation purposes, “non-control” portfolio investments are generally composed of debt and equity securities in companies for which MSC Income does not have a controlling interest in the equity ownership of the portfolio company or the ability to nominate a majority of the portfolio company’s board of directors.

Under the Waterfall valuation method, MSC Income estimates the enterprise value of a portfolio company using a combination of market and income approaches or other appropriate valuation methods, such as considering recent transactions in the equity securities of the portfolio company or third-party valuations of the portfolio company, and then performs a Waterfall calculation by allocating the enterprise value over the portfolio company’s securities in order of their preference relative to one another. The enterprise value is the fair value at which an enterprise could be sold in a transaction between two willing parties, other than through a forced or liquidation sale. Typically, privately held companies are bought and sold based on multiples of earnings before interest, taxes, depreciation and amortization (“EBITDA”), cash flows, net income, revenues, or in limited cases, book value. There is no single methodology for estimating enterprise value. For any one portfolio company, enterprise value is generally described as a range of values from which a single estimate of enterprise value is derived. In estimating the enterprise value of a portfolio company, MSC Income analyzes various factors including the portfolio company’s historical and projected financial results. Due to Securities and Exchange Commission (“SEC”) deadlines for MSC Income’s quarterly and annual financial reporting, the operating results of a portfolio company used in the current period valuation are generally the results from the period ended three months prior to such valuation date and may include unaudited, projected, budgeted or pro forma financial information and may require adjustments for non-recurring items or to normalize the operating results that may require significant judgment in determining. In addition, projecting future financial results requires significant judgment regarding future growth assumptions. In evaluating the operating results, MSC Income also analyzes the impact of exposure to litigation, loss of customers or other contingencies. After determining the appropriate enterprise value, MSC Income allocates the enterprise value to investments in order of the legal priority of the various components of the portfolio company’s capital structure. In applying the Waterfall valuation method, MSC Income assumes the loans are paid-off at the principal amount in a change in control transaction and are not assumed by the buyer, which MSC Income believes is consistent with its past transaction history and standard industry practices.

Under the Yield-to-Maturity valuation method, MSC Income also uses the income approach to determine the fair value of debt securities based on projections of the discounted future free cash flows that the debt security will likely generate, including analyzing the discounted cash flows of interest and principal amounts for the debt security, as set forth in the associated loan agreements, as well as the financial position and credit risk of the portfolio company. MSC Income’s estimate of the expected repayment date of its debt securities is generally the maturity date of the instrument, as MSC Income generally intends to hold its loans and debt securities to maturity. The Yield-to-Maturity analysis also considers changes in leverage levels, credit quality, portfolio company performance, changes in market-based interest rates and other factors. MSC Income will generally use the value determined by the Yield-to-Maturity analysis as the fair value for that security; however, because of MSC Income’s general intent to hold its loans to maturity, the fair value will not exceed the principal amount of the debt security valued using the Yield-to-Maturity valuation method. A change in the assumptions that MSC Income uses to estimate the fair value of its debt securities using the Yield-to-Maturity valuation method could have a material impact on the determination of fair value. If there is deterioration in credit quality or if a debt security is in workout status, MSC Income may consider other factors in determining the fair value of the debt security, including the value attributable to the debt security from the enterprise value of the portfolio company or the proceeds that would most likely be received in a liquidation analysis.

Under the NAV valuation method, for an investment in an investment fund that does not have a readily determinable fair value, MSC Income measures the fair value of the investment predominately based on the NAV of the investment fund as of the measurement date and adjusts the investment’s fair value for factors known to MSC Income that would affect that fund’s NAV, including, but not limited to, fair values for individual investments held by the fund if MSC Income holds the same investment or for a publicly traded investment. In addition, in determining the fair value of the investment, MSC Income considers whether adjustments to the NAV are necessary in certain circumstances, based on the analysis of any restrictions on redemption of MSC Income’s investment as of the measurement date, recent actual sales or redemptions of interests in the investment fund, and expected future cash flows available to equity holders, including the rate of return on those cash flows compared to an implied market return on equity required by market participants, or other uncertainties surrounding MSC Income’s ability to realize the full NAV of its interests in the investment fund.

Pursuant to its internal valuation process and the requirements under the 1940 Act, MSC Income performs valuation procedures on each of its portfolio investments quarterly. In addition to its internal valuation process, in arriving at estimates of fair value for its investments in its Private Loan portfolio companies, MSC Income, among other things, consults with a nationally recognized independent financial advisory services firm (the “Financial Advisory Firm”). The Financial Advisory Firm analyzes and provides observations, recommendations and an assurance certification regarding MSC Income’s determinations of the fair value of its Private Loan portfolio company investments. The Financial Advisory Firm is generally consulted relative to MSC Income’s investments in each Private Loan portfolio company at least once every calendar year, and for MSC Income’s investments in new Private Loan portfolio companies, at least once in thetwelve-month period subsequent to the initial investment. In certain instances, MSC Income may determine that it is not cost-effective, and as a result is not in its stockholders’ best interest, to consult with the Financial Advisory Firm on its investments in one or more Private Loan portfolio companies. Such instances include, but are not limited to, situations where the fair value of MSC Income’s investment in a Private Loan portfolio company is determined to be insignificant relative to the total Investment Portfolio. MSC Income consulted with and received an assurance certification from the Financial Advisory Firm in arriving at its determination of fair value for its investments in a total of 14 and 17 Private Loan portfolio companies during the three months ended September 30, 2025 and 2024, respectively, representing 22% and 24% of the total Private Loan portfolio at fair value as of September 30, 2025 and 2024, respectively. A total of 61 Private Loan portfolio companies were reviewed and certified by the Financial Advisory Firm during the trailing twelve months ended September 30, 2025, representing 90% of the total Private Loan portfolio at fair value as of September 30, 2025. Excluding its investments in Private Loan portfolio companies that, as of September 30, 2025, had not been in the Investment Portfolio for at least twelve months subsequent to the initial investment,96% of the Private Loan portfolio at fair value was reviewed and certified by the Financial Advisory Firm during the trailing twelve months ended September 30, 2025.

For valuation purposes, all of MSC Income’s Private Loan portfolio investments are non-control investments. For Private Loan portfolio investments for which it has determined that third-party quotes or other independent pricing are not available or appropriate, MSC Income generally estimates the fair value based on the assumptions that it believes hypothetical market participants would use to value such Private Loan debt investments in a current hypothetical sale using the Yield-to-Maturity valuation method and such Private Loan equity investments in a current hypothetical sale using the Waterfall valuation method.

In addition to its internal valuation process, in arriving at estimates of fair value for its investments in its LMM portfolio companies, MSC Income, among other things, consults with the Financial Advisory Firm. The Financial Advisory Firm analyzes and provides observations, recommendations and an assurance certification regarding MSC Income’s determinations of the fair value of its LMM portfolio company investments. The Financial Advisory Firm is generally consulted relative to MSC Income’s investments in each LMM portfolio company at least once every calendar year, and for MSC Income’s investments in new LMM portfolio companies, at least once in thetwelve-month period subsequent to the initial investment. In certain instances, MSC Income may determine that it is not cost-effective, and as a result is not in its stockholders’ best interest, to consult with the Financial Advisory Firm on its investments in one or more LMM portfolio companies. Such instances include, but are not limited to, situations where the fair value of MSC Income’s investment in a LMM portfolio company is determined to be insignificant relative to the total Investment Portfolio. MSC Income consulted with and received an assurance certification from the Financial Advisory Firm in arriving at its determination of fair value for its investments in a total of 12 LMM portfolio companies during each of the three months ended September 30, 2025 and 2024, representing 24% and 22% of the total LMM portfolio at fair value as of September 30, 2025 and 2024, respectively. A total of 50 LMM portfolio companies were reviewed and certified by the Financial Advisory Firm during the trailing twelve months ended September 30, 2025, representing 99% of the total LMM portfolio at fair value as of September 30, 2025. Excluding its investments in LMM portfolio companies that, as of September 30, 2025, had not been in the Investment Portfolio for at least twelve months subsequent to the initial investment or whose primary purpose is to own real estate for which a third-party appraisal is obtained on at least an annual basis,99% of the LMM portfolio at fair value was reviewed and certified by the Financial Advisory Firm during the trailing twelve months ended September 30, 2025.

For valuation purposes, all of MSC Income’s Middle Market portfolio investments are non-control investments. To the extent sufficient observable inputs are available to determine fair value, MSC Income uses observable inputs to determine the fair value of these investments through obtaining third-party quotes or other independent pricing. For Middle Market portfolio investments for which it has determined that third-party quotes or other independent pricing are not available or appropriate, MSC Income generally estimates the fair value based on the assumptions that it believes hypothetical market participants would use to value such Middle Market debt investments in a current hypothetical sale using the Yield-to-Maturity valuation method and such Middle Market equity investments in a current hypothetical sale using the Waterfall valuation method. MSC Income generally consults on a limited basis with the Financial Advisory Firm in connection with determining the fair value of its Middle Market portfolio investments due to the nature of these investments. The vast majority (89% and 93% as of September 30, 2025 and December 31, 2024, respectively) of the Middle Market portfolio investments (i) are valued using third-party quotes or other independent pricing services or (ii) MSC Income has consulted with and received an assurance certification from the Financial Advisory Firm within the last twelve months.

For valuation purposes, all of MSC Income’s Other Portfolio investments are non-control investments. MSC Income’s Other Portfolio investments comprised 1.3% and 2.0% of MSC Income’s Investment Portfolio at fair value as of September 30, 2025 and December 31, 2024, respectively. Similar to the LMM investment portfolio, market quotations for Other Portfolio equity investments are generally not readily available. For its Other Portfolio equity investments, MSC Income generally determines the fair value of these investments using the NAV valuation method.

Due to the inherent uncertainty in the valuation process, MSC Income’s determination of fair value for its Investment Portfolio may differ materially from the values that would have been determined had a ready market for the securities existed. In addition, changes in the market environment, portfolio company performance and other events that may occur over the lives of the investments may cause the gains or losses ultimately realized on these investments to be materially different than the valuations currently assigned. MSC Income determines the fair value of each individual investment and records changes in fair value as unrealized appreciation or depreciation.

MSC Income uses an internally developed portfolio investment rating system in connection with its investment oversight, portfolio management and analysis and investment valuation procedures for its Private Loan, LMM and Middle Market portfolio companies. This system takes into account both quantitative and qualitative factors of each Private Loan, LMM and Middle Market portfolio company.

Rule 2a-5 under the 1940 Act permits a BDC’s board of directors to designate its executive officers or investment adviser as a valuation designee to determine the fair value for its investment portfolio, subject to the active oversight of the board. MSC Income’s Board of Directors has approved policies and procedures pursuant to Rule 2a-5 (the “Valuation Procedures”) and has designated the Adviser, led by a group of Main Street’s and the Adviser’s executive officers, to serve as the Board of Directors’ valuation designee. MSC Income believes its Investment Portfolio as of September 30, 2025 and December 31, 2024 approximates fair value as of those dates based on the markets in which it operates and other conditions in existence on those reporting dates.

2. Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the period. Actual results may differ from these estimates under different conditions or assumptions. Additionally, as explained in Note B.1. — Summary of Significant Accounting Policies — Valuation of the Investment Portfolio, the consolidated financial statements include investments in the Investment Portfolio whose values have been estimated by MSC Income pursuant to valuation policies and procedures approved and overseen by MSC Income’s Board of Directors, in the absence of readily ascertainable market values. Because of the inherent uncertainty of the Investment Portfolio valuations, those estimated values may differ materially from the values that would have been determined had a ready market for the securities existed.

Macroeconomic factors, including pandemics, risk of recession, inflation, supply chain constraints or disruptions, geopolitical disruptions, uncertainty with respect to the imposition of tariffs on and trade disputes with certain countries and changing market index interest rates, and the related effect on the U.S. and global economies, have impacted, and may continue to impact, the businesses and operating results of certain of MSC Income’s portfolio companies. As a result of these and other current effects of macroeconomic factors, as well as the uncertainty regarding the extent and duration of their impact, the valuation of MSC Income’s Investment Portfolio has and may continue to experience increased volatility.

3. Cash and Cash Equivalents

Cash and cash equivalents consist of cash and highly liquid investments with an original maturity of three months or less at the date of purchase. Cash and cash equivalents are carried at cost, which approximates fair value. As of September 30, 2025 and December 31, 2024, the Fund had $12.3 million and $14.4 million, respectively, of cash equivalents invested in AAA-rated money market funds pending investment in the Fund’s primary investment strategies. These highly liquid investments are included in the Consolidated Schedule of Investments.

As of September 30, 2025 and December 31, 2024, cash balances totaling $4.8 million and $13.5 million, respectively, exceeded Federal Deposit Insurance Corporation insurance protection levels, subjecting the Fund to risk related to the uninsured balance.

4. Interest, Dividend and Fee Income

MSC Income records interest and dividend income on the accrual basis to the extent amounts are expected to be collected. Dividend income is recorded when dividends are declared by the portfolio company or at such other time that an obligation exists for the portfolio company to make a distribution. MSC Income evaluates accrued interest and dividend income periodically for collectability. When a loan or debt security becomes 90 days or more past due, and if MSC Income otherwise does not expect the debtor to be able to service its debt obligation, MSC Income will generally place the loan or debt security on non-accrual status and cease recognizing interest income on that loan or debt security until the borrower has demonstrated the ability and intent to pay contractual amounts due. If a loan or debt security’s status significantly improves regarding the debtor’s ability to service the debt obligation, or if a loan or debt security is sold or written off, MSC Income removes it from non-accrual status.

As of September 30, 2025, investments on non-accrual status comprised 1.4% of MSC Income’s total Investment Portfolio at fair value and 4.6% at cost. As of December 31, 2024, investments on non-accrual status comprised 1.5% of MSC Income’s total Investment Portfolio at fair value and 5.6% at cost.

MSC Income holds certain debt and preferred equity instruments in its Investment Portfolio that contain PIK interest and cumulative dividend provisions. The PIK interest, computed at the contractual rate specified in each debt agreement, is periodically added to the principal balance of the debt and is recorded as interest income. Thus, the actual collection of this interest may be deferred until the time of debt principal repayment. Cumulative dividends are recorded as dividend income, and any dividends in arrears are added to the balance of the preferred equity investment. The actual collection of these dividends in arrears may be deferred until such time as the preferred equity is redeemed or sold. To maintain RIC tax treatment (as discussed in Note B.8. — Summary of Significant Accounting Policies — Income Taxes below), these non-cash sources of income may need to be paid out to stockholders in the form of distributions, even though MSC Income may not have collected the PIK interest and cumulative dividends in cash. MSC Income stops accruing PIK interest and cumulative dividends and writes off any accrued and uncollected interest and dividends in arrears when it determines that such PIK interest and dividends in arrears are no longer collectible. For the three months ended September 30, 2025 and 2024, (i)6.5% and 6.7%, respectively, of MSC Income’s total investment income was attributable to PIK interest income not paid currently in cash and (ii)0.9% and 0.1%, respectively, of MSC Income’s total investment income was attributable to cumulative dividend income not paid currently in cash. For the nine months ended September 30, 2025 and 2024, (i)5.9% and 5.4%, respectively, of MSC Income’s total investment income was attributable to PIK interest income not paid currently in cash and (ii)0.9% and 0.1%, respectively, of MSC Income’s total investment income was attributable to cumulative dividend income not paid currently in cash.

MSC Income may periodically provide services, including structuring and advisory services, to its portfolio companies or other third parties. For services that are separately identifiable and evidence exists to substantiate fair value, fee income is recognized as earned, which is generally when the investment or other applicable transaction closes. Fees received in connection with debt financing transactions for services that do not meet these criteria are treated as debt origination fees and are generally deferred and accreted into income over the life of the financing.

A presentation of total investment income MSC Income earned from its Investment Portfolio in each of the periods presented is as follows:

5. Deferred Financing Costs

Deferred financing costs include commitment fees and other direct costs incurred in connection with arranging MSC Income’s borrowings. Deferred financing costs incurred in connection with MSC Income’s Credit Facilities (as defined in Note D — Debt) are capitalized as an asset. Deferred financing costs incurred in connection with the Series A Notes (as defined in Note D — Debt) are reflected as a direct deduction from the principal amount outstanding.

6. Equity Offering Costs

The Fund’s offering costs are charged against the proceeds from equity offerings when the proceeds are received.

7. Unearned Income — Debt Origination Fees and Original Issue Discount and Discounts / Premiums to Par Value

MSC Income capitalizes debt origination fees received in connection with financings and reflects such fees as unearned income netted against the applicable debt investments. The unearned income from the fees is accreted into income over the life of the financing.

In connection with its portfolio debt investments, MSC Income sometimes receives nominal cost warrants or warrants with an exercise price below the fair value of the underlying equity (together, “nominal cost equity”) that are valued as part of the negotiation process with the particular portfolio company. When MSC Income receives nominal cost equity, it allocates its cost basis in its investment between its debt security and its nominal cost equity at the time of origination based on amounts negotiated with the particular portfolio company. The allocated amounts are based upon the fair value of the nominal cost equity, which is then used to determine the allocation of cost to the debt security. Any discount recorded on a debt investment resulting from this allocation is reflected as unearned income, which is netted against the applicable debt investment, and accreted into interest income over the life of the debt investment. The actual collection of this interest is deferred until the time of debt principal repayment.

MSC Income may also purchase debt securities at a discount or at a premium to the par value of the debt security. In the case of a purchase at a discount, MSC Income records the investment at the par value of the debt security net of the discount, and the discount is accreted into interest income over the life of the debt investment. In the case of a purchase at a premium, MSC Income records the investment at the par value of the debt security plus the premium, and the premium is amortized as a reduction to interest income over the life of the debt investment.

To maintain RIC tax treatment (as discussed in Note B.8. — Summary of Significant Accounting Policies — Income Taxes below), these non-cash sources of income may need to be paid out to stockholders in the form of distributions, even though MSC Income may not have collected the interest income. For the three months ended September 30, 2025 and 2024,2.4% and 3.0%, respectively, of MSC Income’s total investment income was attributable to interest income from the accretion of discounts associated with debt investments, net of any premium amortization. For the nine months ended September 30, 2025 and 2024,2.4% and 2.8%, respectively, of MSC Income’s total investment income was attributable to interest income from the accretion of discounts associated with debt investments, net of any premium amortization.

8. Income Taxes

MSIF has elected to be treated for U.S. federal income tax purposes as a RIC. MSIF’s taxable income includes the taxable income generated by MSIF and certain of its subsidiaries, including the Structured Subsidiaries, which are treated as disregarded entities for tax purposes. As a RIC, MSIF generally will not pay corporate-level U.S. federal income taxes on any net ordinary taxable income or capital gains that MSIF distributes to its stockholders. MSIF must generally distribute at least 90% of its “investment company taxable income” (which is generally its net ordinary taxable income and realized net short-term capital gains in excess of realized net long-term capital losses) and 90% of its tax-exempt income to maintain its RIC status (pass-through tax treatment for amounts distributed). As part of maintaining RIC status, undistributed taxable income (subject to a 4% non-deductible U.S. federal excise tax) pertaining to a given fiscal year may be distributed up to twelve months subsequent to the end of that fiscal year, provided such dividends are declared on or prior to the later of (i) the filing of the U.S. federal income tax return for the applicable fiscal year or (ii) the fifteenth day of the ninth month following the close of the year in which such taxable income was generated.

The Taxable Subsidiaries primarily hold certain equity investments for MSC Income. The Taxable Subsidiaries permit MSC Income to hold equity investments in portfolio companies which are “pass-through” entities for tax purposes and to continue to comply with the “source-of-income” requirements contained in the RIC tax provisions of the Code. The Taxable Subsidiaries are consolidated with MSC Income for U.S. GAAP financial reporting purposes, and the portfolio investments held by the Taxable Subsidiaries are included in MSC Income’s consolidated financial statements as portfolio investments and recorded at fair value. The Taxable Subsidiaries are not consolidated with MSIF for income tax purposes and may generate income tax expense, or benefit, and tax assets and liabilities, as a result of their ownership of certain portfolio investments. The taxable income, or loss, of the Taxable Subsidiaries may differ from their book income, or loss, due to temporary book and tax timing differences and permanent differences. The Taxable Subsidiaries are each taxed at corporate income tax rates based on their taxable income. The income tax expense, or benefit, if any, and the related tax assets and liabilities, of the Taxable Subsidiaries are reflected in MSC Income’s consolidated financial statements.

The Taxable Subsidiaries use the liability method in accounting for income taxes. Deferred tax assets and liabilities are recorded for temporary differences between the tax basis of assets and liabilities and their reported amounts in the consolidated financial statements, using statutory tax rates in effect for the year in which the temporary differences are expected to reverse. A valuation allowance is provided, if necessary, against deferred tax assets when it is more likely than not that some portion or all of the deferred tax asset will not be realized. MSC Income’s net assets as included on the Consolidated Balance Sheets and Consolidated Statements of Changes in Net Assets include an adjustment to classification as a result of permanent book-to-tax differences, which include differences in the book and tax treatment of income and expenses.

Taxable income generally differs from net income for financial reporting purposes due to temporary and permanent differences in the recognition of income and expenses. Taxable income generally excludes net unrealized appreciation or depreciation, as investment gains or losses are not included in taxable income until they are realized.

9. Net Realized Gains or Losses and Net Unrealized Appreciation or Depreciation

Realized gains or losses are measured by the difference between the net proceeds from the sale or redemption of an investment or a financial instrument and the cost basis of the investment or financial instrument, without regard to unrealized appreciation or depreciation previously recognized, and includes investments written-off during the period net of recoveries and realized gains or losses from in-kind redemptions. Net unrealized appreciation or depreciation reflects the net change in the fair value of the Investment Portfolio and financial instruments and the reclassification of any prior period unrealized appreciation or depreciation on exited investments and financial instruments to realized gains or losses.

10. Fair Value of Financial Instruments

Fair value estimates are made at discrete points in time based on relevant information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and, therefore, cannot be determined with precision. MSC Income believes that the carrying amounts of its financial instruments, consisting of cash and cash equivalents, receivables, payables and other liabilities approximate the fair values of such items due to the short-term nature of these instruments.

MSC Income’s debt instruments, including all revolving and term debt, are accounted for on a historical cost basis as applicable under U.S. GAAP. As also required under U.S. GAAP, MSC Income discloses the estimated fair value of its debt obligations in Note D — Debt. To estimate the fair value of MSC Income’s Series A Notes as disclosed in Note D — Debt, MSC Income uses the Yield-to-Maturity valuation method based on projections of the discounted future free cash flows that the debt security will likely generate, including both the discounted cash flows of the associated interest and principal amounts for the debt security. The inputs used to value MSC Income’s debt instruments for purposes of the fair value estimate disclosures in Note D — Debt are considered to be Level 2 according to the ASC 820 fair value hierarchy.

11. Earnings Per Share

Basic and diluted per share calculations, including net increase in net assets resulting from operations per share and net investment income per share, are computed utilizing the weighted-average number of shares of common stock outstanding for the period.

12. Segments

MSC Income operates as a single segment with a principal investment objective to maximize total return primarily by generating current income from debt investments and, to a lesser extent, by generating current income and capital appreciation from equity and equity-related investments. The Adviser’s Investment Committee and the Fund’s Chief Executive Officer collectively perform the function that allocates resources and assesses performance, and thus together, serve as the Fund’s chief operating decision maker (the “CODM”). Among other metrics, the CODM uses net investment income as a primary U.S. GAAP profit or loss metric used in making operating decisions, which can be found on the Consolidated Statement of Operations along with significant expenses. The measure of segment assets is reported on the Consolidated Balance Sheets as total assets.

13. Recently Issued or Adopted Accounting Standards

In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures. The amendments in this update require more disaggregated information on income taxes paid. ASU 2023-09 is effective for years beginning after December 15, 2024, and early adoption is permitted. The Fund has determined that ASU 2023-09 will not have a material impact on the consolidated financial statements and the notes thereto.

From time to time, new accounting pronouncements are issued by the FASB or other standards-setting bodies that are adopted by the Fund as of the specified effective date. The Fund believes that the impact of recently issued standards and any that are not yet effective will not have a material impact on its consolidated financial statements upon adoption.

NOTE C —FAIR VALUE HIERARCHY FOR INVESTMENTS — PORTFOLIO COMPOSITION

ASC 820 defines fair value, establishes a framework for measuring fair value, establishes a fair value hierarchy based on the quality of inputs used to measure fair value, and enhances disclosure requirements for fair value measurements. MSC Income accounts for its investments at fair value.

Fair Value Hierarchy

In accordance with ASC 820, MSC Income has categorized its investments based on the priority of the inputs to the valuation technique into a three-level fair value hierarchy. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical investments (Level 1) and the lowest priority to unobservable inputs (Level 3).

Investments recorded on MSC Income’s Consolidated Balance Sheets are categorized based on the inputs to the valuation techniques as follows:

Level 1 — Investments whose values are based on unadjusted quoted prices for identical assets in an active market that MSC Income has the ability to access (examples include investments in active exchange-traded equity securities and investments in most U.S. government and agency securities).

Level 2 — Investments whose values are based on quoted prices in markets that are not active or model inputs that are observable either directly or indirectly for substantially the full term of the investment. Level 2 inputs include the following:

•Quoted prices for similar assets in active markets (for example, investments in restricted stock);

•Quoted prices for identical or similar assets in non-active markets (for example, investments in thinly traded public companies);

•Pricing models whose inputs are observable for substantially the full term of the investment (for example, market interest rate indices); and

•Pricing models whose inputs are derived principally from, or corroborated by, observable market data through correlation or other means for substantially the full term of the investment.

Level 3 — Investments whose values are based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement (for example, investments in illiquid securities issued by privately held companies). These inputs reflect management’s own assumptions about the assumptions a market participant would use in pricing the investment.

As required by ASC 820, when the inputs used to measure fair value fall within different levels of the hierarchy, the level within which the fair value measurement is categorized is based on the lowest level input that is significant to the fair value measurement in its entirety. For example, a Level 3 fair value measurement may include inputs that are observable (Levels 1 and 2) and unobservable (Level 3). Therefore, unrealized appreciation and depreciation related to such investments categorized within the Level 3 tables below may include changes in fair value that are attributable to both observable inputs (Levels 1 and 2) and unobservable inputs (Level 3).

As of September 30, 2025 and December 31, 2024, all of MSC Income’s Private Loan portfolio investments consisted of illiquid securities issued by privately held companies. The fair value determination for these investments consisted of a combination of observable inputs in non-active markets for which sufficient observable inputs were not available to determine the fair value of these investments and unobservable inputs. As a result, all of MSC Income’s Private Loan portfolio investments were categorized as Level 3 as of September 30, 2025 and December 31, 2024.

As of September 30, 2025 and December 31, 2024, all of MSC Income’s LMM portfolio investments consisted of illiquid securities issued by privately held companies and the fair value determination for these investments primarily consisted of unobservable inputs. As a result, all of MSC Income’s LMM portfolio investments were categorized as Level 3 as of September 30, 2025 and December 31, 2024.

As of September 30, 2025 and December 31, 2024, MSC Income’s Middle Market portfolio investments consisted primarily of investments in secured and unsecured debt investments and independently rated debt investments. The fair value determination for these investments consisted of a combination of observable inputs in non-active markets for which sufficient observable inputs were not available to determine the fair value of these investments and unobservable inputs. As a result, all of MSC Income’s Middle Market portfolio investments were categorized as Level 3 as of September 30, 2025 and December 31, 2024.

As of September 30, 2025 and December 31, 2024, all of MSC Income’s Other Portfolio investments consisted of illiquid securities issued by privately held entities and the fair value determination for these investments primarily consisted of unobservable inputs. As a result, all of MSC Income’s Other Portfolio investments were categorized as Level 3 as of September 30, 2025 and December 31, 2024.

As of September 30, 2025 and December 31, 2024, all money market funds included in cash and cash equivalents were valued using Level 1 inputs.

The fair value determination of each portfolio investment categorized as Level 3 required one or more of the following unobservable inputs:

•Financial information obtained from each portfolio company, including unaudited statements of operations and balance sheets for the most recent period available as compared to budgeted information;

•Current and projected financial condition of the portfolio company;

•Current and projected ability of the portfolio company to service its debt obligations;

•Type and amount of collateral, if any, underlying the investment;

•Current financial ratios (e.g., fixed charge coverage ratio, interest coverage ratio and net debt/EBITDA ratio) applicable to the investment;

•Current liquidity of the investment and related financial ratios (e.g., current ratio and quick ratio);

•Pending debt or capital restructuring of the portfolio company;

•Projected operating results of the portfolio company;

•Current information regarding any offers to purchase the investment;

•Current ability of the portfolio company to raise any additional financing as needed;

•Changes in the economic environment which may have a material impact on the operating results of the portfolio company;

•Internal occurrences that may have an impact (both positive and negative) on the operating performance of the portfolio company;

•Qualitative assessment of key management;

•Contractual rights, obligations or restrictions associated with the investment; and

•Other factors deemed relevant.

The use of significant unobservable inputs creates uncertainty in the measurement of fair value as of the reporting date. The significant unobservable inputs used in the fair value measurement of MSC Income’s LMM equity securities, which are generally valued through an average of the discounted cash flow technique and the market comparable/enterprise value technique (unless one of these approaches is determined to not be appropriate), are (i) EBITDA multiples and (ii) the weighted-average cost of capital (“WACC”). Significant increases (decreases) in EBITDA multiple inputs in isolation would result in a significantly higher (lower) fair value measurement, and significant increases (decreases) in WACC inputs in isolation would result in a significantly lower (higher) fair value measurement. The significant unobservable inputs used in the fair value measurement of MSC Income’s Private Loan, LMM and Middle Market debt securities are (i) risk adjusted discount rates used in the Yield-to-Maturity valuation technique (see Note B.1. — Summary of Significant Accounting Policies — Valuation of the Investment Portfolio) and (ii) the percentage of expected principal recovery. Significant increases (decreases) in any of these discount rates in isolation would result in a significantly lower (higher) fair value measurement. Significant increases (decreases) in any of these expected principal recovery percentages in isolation would result in a significantly higher (lower) fair value measurement. However, due to the nature of certain investments, fair value measurements may be based on other criteria, such as third-party appraisals of collateral and fair values as determined by independent third parties, which are not presented in the tables below.

The following tables provide a summary of the significant unobservable inputs used in the fair value measurement of MSC Income’s Level 3 portfolio investments as of September 30, 2025 and December 31, 2024:

(1)EBITDA may include pro forma adjustments and/or other add-backs based on specific circumstances related to each investment.

(2)Range excludes outliers that are greater than one standard deviation from the mean. Including these outliers, the range for EBITDA multiple is 2.0 x -13.5 x and the range for risk adjusted discount rate is 5.7% -40.6%.

(3)Does not include investments for which the valuation technique does not include the use of the applicable fair value input.

(4)Weighted-average is calculated for each significant unobservable input based on the applicable security’s fair value.

(5)Discount rate includes the effect of the standard SOFR base rate, as applicable.

(1)EBITDA may include pro forma adjustments and/or other add-backs based on specific circumstances related to each investment.

(2)Range excludes outliers that are greater than one standard deviation from the mean. Including these outliers, the range for EBITDA multiple is 2.0 x -17.0 x and the range for risk adjusted discount rate is 6.8% -38.3%.

(3)Does not include investments for which the valuation technique does not include the use of the applicable fair value input.

(4)Weighted-average is calculated for each significant unobservable input based on the applicable security’s fair value.

(5)Discount rate includes the effect of the standard SOFR base rate, as applicable.

The following tables provide a summary of changes in fair value of MSC Income’s Level 3 portfolio investments for the nine months ended September 30, 2025 and 2024 (amounts in thousands):

(1)Includes the impact of non-cash conversions. These transactions represent non-cash investing activities. See additional cash flow information in the Consolidated Statements of Cash Flows.

(1)Includes the impact of non-cash conversions. These transactions represent non-cash investing activities. See additional cash flow information in the Consolidated Statements of Cash Flows.

As of September 30, 2025 and December 31, 2024, MSC Income’s investments at fair value were categorized as follows in the fair value hierarchy for ASC 820 purposes:

Investment Portfolio Composition

MSC Income’s principal investment objective is to maximize its portfolio’s total return, primarily by generating current income from its debt investments and, to a lesser extent, by generating current income and capital appreciation from its equity and equity-related investments, including warrants, convertible securities and other rights to acquire equity securities in a portfolio company. MSC Income seeks to achieve its investment objective primarily by providing debt capital to companies in its Private Loan investment strategy and secondarily through its LMM investment portfolio.

MSC Income’s Private Loan investment strategy is focused on investments in secured debt in privately held companies that generally have annual revenues between $25 million and $500 million, and its Private Loan investments generally range in size from $1 million to $30 million. MSC Income’s Private Loan investments primarily consist of debt securities that have primarily been originated directly by the Adviser or, to a lesser extent, through the Adviser’s strategic relationships with other investment funds on a collaborative basis through investments that are often referred to in the debt markets as “club deals” because of the small lender group size. In both cases, MSC Income’s Private Loan investments are typically made in a company owned by or in the process of being acquired by a private equity fund. MSC Income’s Private Loan portfolio debt investments are generally secured by a first priority lien on the assets of the portfolio company and typically have a term of between three andseven years from the original investment date. MSC Income may also co-invest with Main Street and the private equity fund in the equity securities of its Private Loan portfolio companies.

MSC Income maintains a LMM investment portfolio with investments in secured debt and equity investments in privately held, LMM companies based in the United States. MSC Income’s LMM portfolio companies generally have annual revenues between $10 million and $150 million, and its LMM investments generally range in size from $1 million to $30 million. The LMM portfolio debt investments are typically secured by a first priority lien on the assets of the portfolio company, can include either fixed or floating interest rates and generally have a term of between five andseven years from the original investment date. MSC Income typically makes direct equity investments and/or receives nominally priced equity warrants in connection with a LMM portfolio company debt investment.

In connection with the MSC Income Listing, the Fund changed its investment strategy with respect to new platform investments to be solely focused on the Private Loan investment strategy. As a result, the size of the Fund’s LMM investment portfolio is expected to decrease over time as existing LMM investments are repaid or sold in the ordinary course of business. The Fund does, however, plan to continue executing follow-on investments in its existing LMM portfolio companies going forward in accordance with its existing SEC order for co-investment exemptive relief.

MSC Income also maintains a legacy portfolio of investments in Middle Market companies. MSC Income’s Middle Market investments are generally debt investments in companies owned by a private equity fund that were originally issued through a syndication financing process. MSC Income has generally stopped making new Middle Market investments and expects the size of its Middle Market investment portfolio to continue to decline in future periods as its existing Middle Market investments are repaid or sold. MSC Income’s Middle Market debt investments generally range in size from $1 million to $20 million, are generally secured by a first priority lien on the assets of the portfolio company and typically have an expected duration of between three andseven years from the original investment date.

MSC Income’s Other Portfolio investments primarily consist of investments that are not consistent with the typical profiles for its Private Loan, LMM or Middle Market portfolio investments, including investments in unaffiliated investment companies and private funds managed by third parties. In the Other Portfolio, MSC Income may incur indirect fees and expenses in connection with investments managed by third parties, such as investments in other investment companies or private funds. For Other Portfolio investments, MSC Income generally receives distributions related to the assets held by the portfolio company. Those assets are typically expected to be realized over afive toten-year period. Similar to its Middle Market investments, the Fund has generally stopped making new Other Portfolio investments and expects the size of its Other Portfolio to continue to decline in future periods as existing Other Portfolio investments are repaid or sold.

Based upon MSC Income’s liquidity and capital structure management activities, MSC Income’s Investment Portfolio may also periodically include short-term portfolio investments that are atypical of MSC Income’s Private Loan and LMM portfolio investments in that they are intended to be a short-term deployment of capital. Those assets are typically expected to be realized in one year or less. These short-term portfolio investments are not expected to be a significant portion of the overall Investment Portfolio.

Investment income, consisting of interest, dividends and fees, can fluctuate dramatically due to various factors, including the level of new investment activity, repayments of debt investments or sales of equity interests. Investment income in any given year could also be highly concentrated among several portfolio companies. For the three and nine months ended September 30, 2025 and 2024, MSC Income did not record investment income from any single portfolio company in excess of 10% of total investment income.

The following tables provide a summary of MSC Income’s investments in the Private Loan and LMM portfolios as of September 30, 2025 and December 31, 2024 (this information excludes Middle Market and Other Portfolio investments, which are discussed further below).

(a)As of September 30, 2025, MSC Income had equity ownership in all of its LMM portfolio companies, and the average fully diluted equity ownership in those portfolio companies was 9%.

(b)The weighted-average annual effective yields were computed using the effective interest rates for all debt investments as of September 30, 2025, including amortization of deferred debt origination fees and accretion of original issue discount but excluding fees payable upon repayment of the debt instruments and any debt investments on non-accrual status, and are weighted based upon the principal amount of each applicable debt investment as of September 30, 2025. The weighted-average annual effective yield on MSC Income’s debt portfolio as of September 30, 2025, including debt investments on non-accrual status, was 10.4% for its Private Loan portfolio and 12.1% for its LMM portfolio. The weighted-average annual effective yield is not reflective of what an investor in shares of MSC Income’s common stock will realize on its investment because it does not reflect changes in the market value of MSC Income’s stock, MSC Income’s utilization of debt capital in its capital structure, MSC Income’s expenses or any sales load paid by an investor.

(c)The average EBITDA is calculated using a weighted-average for the Private Loan portfolio and a simple average for the LMM portfolio. These calculations exclude certain portfolio companies, including four Private Loan portfolio companies andthree LMM portfolio companies, as EBITDA is not a meaningful valuation metric for MSC Income’s investments in these portfolio companies, and those portfolio companies whose primary purpose is to own real estate and those portfolio companies whose primary operations have ceased and only residual value remains.

(a)As of December 31, 2024, MSC Income had equity ownership in all of its LMM portfolio companies, and the average fully diluted equity ownership in those portfolio companies was 9%.

(b)The weighted-average annual effective yields were computed using the effective interest rates for all debt investments as of December 31, 2024, including amortization of deferred debt origination fees and accretion of original issue discount but excluding fees payable upon repayment of the debt instruments and any debt investments on non-accrual status, and are weighted based upon the principal amount of each applicable debt investment as of December 31, 2024. The weighted-average annual effective yield on MSC Income’s debt portfolio as of December 31, 2024, including debt investments on non-accrual status, was 11.4% for its Private Loan portfolio and 12.2% for its LMM portfolio. The weighted-average annual effective yield is not reflective of what an investor in shares of MSC Income’s common stock will realize on its investment because it does not reflect MSC Income’s utilization of debt capital in its capital structure, MSC Income’s expenses or any sales load paid by an investor.

(c)The average EBITDA is calculated using a weighted-average for the Private Loan portfolio and a simple average for the LMM portfolio. These calculations exclude certain portfolio companies, includingtwo Private Loan portfolio companies andthree LMM portfolio companies, as EBITDA is not a meaningful valuation metric for MSC Income’s investments in these portfolio companies, and those portfolio companies whose primary purpose is to own real estate and those portfolio companies whose primary operations have ceased and only residual value remains.

For the three months ended September 30, 2025 and 2024, MSC Income achieved an annualized total return on investments of 15.7% and 10.5%, respectively. For the nine months ended September 30, 2025 and 2024, MSC Income achieved an annualized total return on investments of 12.8% and 12.4%, respectively. For the year ended December 31, 2024, MSC Income achieved a total return on investments of 12.4%. Total return on investments equals the total interest, dividend and fee income plus realized and unrealized changes in the fair value of the Investment Portfolio divided by the average quarterly Investment Portfolio balance at cost, in each case for the specified period. MSC Income’s total return on investments is not reflective of what an investor in shares of MSC Income’s common stock will realize on its investment because it does not reflect changes in the market value of MSC Income’s stock, MSC Income’s utilization of debt capital in its capital structure, MSC Income’s expenses or any sales load paid by an investor.

As of September 30, 2025, MSC Income had Middle Market portfolio investments ineight portfolio companies, collectively totaling $26.6 million in fair value and $40.0 million in cost basis, which comprised 2.1% and 3.4% of MSC Income’s Investment Portfolio at fair value and cost, respectively. As of December 31, 2024, MSC Income had Middle Market Portfolio investments inten portfolio companies, collectively totaling $39.4 million in fair value and $66.3 million in cost basis, which comprised 3.3% and 5.8% of MSC Income’s Investment Portfolio at fair value and cost, respectively.

As of September 30, 2025, MSC Income had Other Portfolio investments insix entities, spread across four investment managers, collectively totaling $16.0 million in fair value and $14.3 million in cost basis, which comprised 1.3% and 1.2% of MSC Income’s Investment Portfolio at fair value and cost, respectively. As of December 31, 2024, MSC Income had Other Portfolio investments insix entities, spread across four investment managers, collectively totaling $24.1 million in fair value and $17.9 million in cost basis, which comprised 2.0% and 1.6% of MSC Income’s Investment Portfolio at fair value and cost, respectively.

The following tables summarize the composition of MSC Income’s total combined Private Loan, LMM and Middle Market portfolio investments at cost and fair value by type of investment as a percentage of the total combined Private Loan, LMM and Middle Market portfolio investments, as of September 30, 2025 and December 31, 2024 (this information excludes Other Portfolio investments, which are discussed above).

The following tables summarize the composition of MSC Income’s total combined Private Loan, LMM and Middle Market portfolio investments by geographic region of the United States and other countries at cost and fair value as a percentage of the total combined Private Loan, LMM and Middle Market portfolio investments, as of September 30, 2025 and December 31, 2024 (this information excludes Other Portfolio investments). The geographic composition is determined by the location of the corporate headquarters of the portfolio company.

MSC Income’s Private Loan, LMM and Middle Market portfolio investments are in companies conducting business in a variety of industries. The following tables summarize the composition of MSC Income’s total combined Private Loan, LMM and Middle Market portfolio investments by industry at cost and fair value as of September 30, 2025 and December 31, 2024 (this information excludes Other Portfolio investments).

(1)Includes various industries with each industry individually less than 1.0% of the total combined Private Loan, LMM and Middle Market portfolio investments at each date.

(1)Includes various industries with each industry individually less than 1.0% of the total combined Private Loan, LMM and Middle Market portfolio investments at each date.

As of September 30, 2025 and December 31, 2024, MSC Income had no portfolio investment that was greater than 10% of the Investment Portfolio at fair value.

Unconsolidated Significant Subsidiaries

In accordance with Rules 3-09 and 4-08(g) of Regulation S-X, MSC Income must determine which of its unconsolidated controlled portfolio companies, if any, are considered “significant subsidiaries.” In evaluating its unconsolidated controlled portfolio companies in accordance with Regulation S-X, there are two tests that MSC Income must utilize to determine if any of MSC Income’s Control investments (as defined in Note A — Organization and Basis of Presentation), including those unconsolidated portfolio companies defined as Control investments in which MSC Income does not own greater than 50% of the voting securities nor have rights to maintain greater than 50% of the board representation, are considered significant subsidiaries: the investment test and the income test. The investment test is generally measured by dividing the fair value of MSC Income’s investment in the Control investment by the fair value of MSC Income’s total investments. The income test is generally measured by dividing the absolute value of the combined sum of total investment income, net realized gain (loss) and net unrealized appreciation (depreciation) from the relevant Control investment for the period being tested by the absolute value of MSC Income’s change in net assets resulting from operations for the same period. Rules 3-09 and 4-08(g) of Regulation S-X require MSC Income to include (1) separate audited financial statements of an unconsolidated majority-owned subsidiary (Control investments in which MSC Income owns greater than 50% of the voting securities) in an annual report and (2) summarized financial information of a Control investment in a quarterly report, respectively, if certain thresholds of the investment or income tests are exceeded and the unconsolidated portfolio company qualifies as a significant subsidiary.

As of September 30, 2025 and December 31, 2024, MSC Income had no single investment that qualified as a significant subsidiary under either the investment or income tests.

NOTE D —DEBT

The following table provides a summary of MSC Income’s debt as of September 30, 2025.

(1)The unamortized debt issuance costs for the Credit Facilities are reflected as Deferred financing costs on the Consolidated Balance Sheets, while the deferred debt issuance costs related to the Series A Notes are reflected as a contra-liability to the Series A Notes on the Consolidated Balance Sheets.

(2)Estimated fair value for outstanding debt is shown as if MSC Income had adopted the fair value option under ASC 825, Financial Instruments(“ASC 825”). See discussion of the methods used to estimate the fair value of MSC Income’s debt in Note B.10. — Summary of Significant Accounting Policies — Fair Value of Financial Instruments.

The following table provides a summary of MSC Income’s debt as of December 31, 2024.

(1)The unamortized debt issuance costs for the Credit Facilities are reflected as Deferred financing costs on the Consolidated Balance Sheets, while the deferred debt issuance costs related to the Series A Notes are reflected as a contra-liability to the Series A Notes on the Consolidated Balance Sheets.

(2)Estimated fair value for outstanding debt is shown as if MSC Income had adopted the fair value option under ASC 825. See discussion of the methods used to estimate the fair value of MSC Income’s debt in Note B.10. — Summary of Significant Accounting Policies — Fair Value of Financial Instruments.

Summarized interest expense for the three and nine months ended September 30, 2025 and 2024 is as follows:

A summary of MSC Income’s average amount of total borrowings outstanding and overall weighted-average effective interest rate including amortization of debt issuance costs, original issuance discounts and premiums and fees on unused lender commitments are as follows:

SPV Facility

MSC Income, through MSIF Funding, LLC (“MSIF Funding”), a wholly-owned Structured Subsidiary that primarily holds debt investments, maintains a special purpose vehicle revolving credit facility dated February 3, 2021 (as amended, the “SPV Facility”) with JPMorgan Chase Bank, National Association (“JPM”), as administrative agent, and U.S. Bank, N.A., as collateral agent and collateral administrator, JPM and other financial institutions as lenders and MSIF as portfolio manager. In March 2025, the SPV Facility was amended to, among other things: (i) decrease the interest rate for advances to the applicable SOFR plus 2.20% from the prior interest rate of the applicable SOFR plus 3.00%, (ii) extend the revolving period from through February 2027 to through February 2029 and (iii) extend the final maturity date from February 2028 to February 2030.

As of September 30, 2025, the SPV Facility included (i) total commitments of $300.0 million, (ii) an accordion feature with the right to request an increase of total commitments and borrowing availability up to $450.0 million and (iii) a revolving period through February 2029 and a final maturity date in February 2030. As of September 30, 2025, advances under the SPV Facility bore interest at a rate equal to the applicable SOFR in effect, plus a margin of 2.20%. MSIF Funding also pays a commitment fee of 0.75% on the average daily unused amount of the financing commitments until February 2029. The SPV Facility is secured by a first lien on the assets of MSIF Funding. Borrowing availability under the SPV Facility is subject to certain leverage and borrowing base limitations, covenants, reporting and other requirements customary for similar credit facilities.

As of September 30, 2025, the interest rate for borrowings on the SPV Facility was 6.49%. The average interest rate for borrowings under the SPV Facility was 6.49% and 8.32% for the three months ended September 30, 2025 and 2024, respectively, and 6.74% and 8.32% for the nine months ended September 30, 2025 and 2024, respectively. As of September 30, 2025, MSC Income was in compliance with all financial covenants of the SPV Facility.

Corporate Facility

MSC Income maintains a senior secured revolving credit agreement dated March 6, 2017 (as amended, the “Corporate Facility” and, together with the SPV Facility, the “Credit Facilities”) with EverBank, as administrative agent, and with EverBank and other financial institutions as lenders.

As of September 30, 2025, the Corporate Facility included (i) total commitments of $245.0 million from a diversified group ofseven lenders, (ii) an accordion feature with the right to request an increase in commitments under the facility from new and existing lenders on the same terms and conditions as the existing commitments up to $300.0 million of total commitments and (iii) a revolving period through November 2028 and a final maturity date in May 2029, withtwo one-year extension options subject to lender approval.

Borrowings under the Corporate Facility bear interest, subject to MSC Income’s election, at a rate equal to (i) SOFR plus 2.05% or (ii) the base rate plus 1.05%. The base rate is defined as the higher of (a) the Prime rate, (b) the Federal Funds Rate (as defined in the credit agreement) plus 0.5% or (c) SOFR plus 1.0%. Additionally, MSC Income pays an unused commitment fee of 0.25% on the unused lender commitments if 50% or more of the lender commitments are being used and an unused commitment fee of 0.375% on the unused lender commitments if less than 50% of the lender commitments are being used. Borrowings under the Corporate Facility are secured by a first lien on all of the assets of MSIF and its subsidiaries, excluding the assets of Structured Subsidiaries or immaterial subsidiaries, as well as all of the assets, and a pledge of equity ownership interests, of any future subsidiaries of MSIF (other than Structured Subsidiaries or immaterial subsidiaries). Borrowing availability under the Corporate Facility is subject to certain leverage and borrowing base limitations, covenants, reporting and other requirements customary for similar credit facilities.

As of September 30, 2025, the interest rate for borrowings on the Corporate Facility was 6.37%. The average interest rate for borrowings under the Corporate Facility was 6.38% and 7.81% for the three months ended September 30, 2025 and 2024, respectively, and 6.38% and 7.82% for the nine months ended September 30, 2025 and 2024, respectively. As of September 30, 2025, MSC Income was in compliance with all financial covenants of the Corporate Facility.

Series A Notes

Pursuant to a Master Note Purchase Agreement dated October 21, 2021 (the “Note Purchase Agreement”), MSC Income issued $77.5 million of 4.04% Series A Senior Notes due 2026 (the “Series A Notes”) upon entering into the Note Purchase Agreement and an additional $72.5 million on January 21, 2022. The Series A Notes bear a fixed interest rate of 4.04% per year and mature on October 30, 2026, unless redeemed, purchased or prepaid prior to such date by the Fund in accordance with their terms.

Interest on the Series A Notes is due semiannually on April 30 and October 30 of each year. The Series A Notes may be redeemed in whole or in part at any time at MSC Income’s option subject to certain make-whole provisions. In addition, MSC Income is obligated to offer to prepay the Series A Notes at par plus accrued and unpaid interest up to, but excluding, the date of prepayment, if certain change in control events occur. In the event that a Below Investment Grade Event (as defined in the Note Purchase Agreement) occurs, the Series A Notes will bear interest at a fixed rate of 5.04% per year from the date of the occurrence of the Below Investment Grade Event to and until the date on which the Below Investment Grade Event ends. The Series A Notes are general unsecured obligations of MSIF that rank pari passu with all outstanding and future unsecured unsubordinated indebtedness issued by MSIF.

The Note Purchase Agreement also contains customary events of default with customary cure and notice periods, including, without limitation, nonpayment, incorrect representation in any material respect, breach of covenant, cross-default under other indebtedness of MSIF or subsidiary guarantors subject to a cure pass-through, certain judgments and orders and certain events of bankruptcy. As of September 30, 2025, MSC Income was in compliance with all covenants and other requirements of the Note Purchase Agreement.

NOTE E —FINANCIAL HIGHLIGHTS

The following is a schedule of financial highlights of MSC Income for the nine months ended September 30, 2025 and 2024:

(1)Based on weighted-average number of common shares outstanding for the period.

(2)Net realized gains or losses, net unrealized appreciation or depreciation, and the related income tax provision or benefit can fluctuate significantly from period to period.

(3)MSIF’s taxable income for each period is an estimate and will not be finally determined until MSIF files its tax return for each year. As a result, the character of MSIF’s dividends and distributions for each period is also an estimate. Therefore, the final character of MSIF’s dividends and distributions may be different than this estimate.

(4)Includes the impact of the different share amounts as a result of calculating certain per share data based on the weighted-average basic shares outstanding during the period and certain per share data based on the shares outstanding as of a period end or transaction date.

(1)Total expenses are the sum of operating expenses and all tax expenses. The total tax provision or benefit includes the accrual of net deferred tax provision or benefit relating to book versus tax differences on income at the Taxable Subsidiaries that is included in net investment income, the net unrealized appreciation or depreciation on portfolio investments held in Taxable Subsidiaries and due to the change in the loss carryforwards, which are non-cash in nature and may vary significantly from period to period. MSC Income is required to include net deferred tax provision or benefit in calculating its total expenses even though these net deferred taxes are not currently payable or receivable.

(2)Not annualized.

(3)Unless otherwise noted, operating expenses include interest, management fees, incentive fees and general and administrative expenses.

(4)For the nine months ended September 30, 2025, total investment return is based on the purchase of stock in the MSC Income Offering at the public offering price of $15.53 and a sale at the current market price on September 30, 2025 and assumes reinvestment of dividends at prices obtained by MSC Income’s DRIP (as defined below) during the period. The return does not reflect any sales load that may be paid by an investor.

(5)For the nine months ended September 30, 2025, total return based on change in NAV was calculated using the sum of ending NAV plus dividends to stockholders and other non-operating changes during the period, divided by the beginning NAV. Non-operating changes include any items that affect NAV other than the net increase in net assets resulting from operations, such as the effects of stock offerings, shares issued under the DRIP, shares repurchased by the Fund and other miscellaneous items. For the nine months ended September 30, 2024, total return was calculated based on the change in NAV per share and stockholder distributions declared per share during the reporting period, divided by the NAV per share at the beginning of the period. In each of the nine months ended September 30, 2025 and 2024, the total return does not reflect the sales load from the sale of MSC Income’s common stock.

(6)Ratios include internal administrative services expense waivers of $6.7 million for the nine months ended September 30, 2024. There wereno internal administrative services expense waivers for the nine months ended September 30, 2025. Excluding these internal administrative services expense waivers, the expense and income ratios are as follows:

See footnotes (1), (2), and (3) immediately prior to this table.

NOTE F —DIVIDENDS, DISTRIBUTIONS AND TAXABLE INCOME

MSC Income currently pays regular quarterly dividends to its stockholders and periodically pays supplemental dividends to its stockholders. Future dividends, if any, will be determined by its Board of Directors on a quarterly basis.

The following table provides asummary of dividends accrued during the three and nine months ended September 30, 2025 and 2024.

MSIF has elected to be treated for U.S. federal income tax purposes as a RIC. MSIF’s taxable income includes the taxable income generated by MSIF and certain of its subsidiaries, including the Structured Subsidiaries, which are treated as disregarded entities for tax purposes. As a RIC, MSIF generally will not pay corporate-level U.S. federal income taxes on any net ordinary taxable income or capital gains that MSIF distributes to its stockholders. MSIF must generally distribute at least 90% of its “investment company taxable income” (which is generally its net ordinary taxable income and realized net short-term capital gains in excess of realized net long-term capital losses) and 90% of its tax-exempt income to maintain its RIC status (pass-through tax treatment for amounts distributed). As part of maintaining RIC status, undistributed taxable income (subject to a 4% non-deductible U.S. federal excise tax) pertaining to a given fiscal year may be distributed up to twelve months subsequent to the end of that fiscal year, provided such dividends are declared on or prior to the later of (i) filing of the U.S. federal income tax return for the applicable fiscal year or (ii) the fifteenth day of the ninth month following the close of the year in which such taxable income was generated.

The determination of the tax attributes for MSC Income’s distributions is made annually, based upon its taxable income for the full year and distributions paid for the full year. Therefore, a determination made on an interim basis may not be representative of the actual tax attributes of distributions for a full year. Ordinary dividend distributions from a RIC do not qualify for the 20% maximum tax rate (plus a 3.8% Medicare surtax, if applicable) on dividend income from domestic corporations and qualified foreign corporations, except to the extent that the RIC received the income in the form of qualifying dividends from domestic corporations and qualified foreign corporations. The tax attributes for distributions will generally include both ordinary income and qualified dividends, but may also include either one or both of capital gains and return of capital.

Listed below is a reconciliation of “Net increase in net assets resulting from operations” to taxable income and to total distributions declared to common stockholders for the nine months ended September 30, 2025 and 2024.

(1)MSIF’s taxable income for each period is an estimate and will not be finally determined until MSIF files its tax return for each year. Therefore, the final taxable income, and the taxable income earned in each period and carried forward for distribution in the following period, may be different than this estimate.

The Taxable Subsidiaries primarily hold certain equity investments for MSC Income. The Taxable Subsidiaries permit MSC Income to hold equity investments in portfolio companies which are “pass-through” entities for tax purposes and to continue to comply with the “source-of-income” requirements contained in the RIC tax provisions of the Code. The Taxable Subsidiaries are consolidated with MSIF for U.S. GAAP financial reporting purposes, and the portfolio investments held by the Taxable Subsidiaries are included in MSC Income’s consolidated financial statements as portfolio investments and recorded at fair value. The Taxable Subsidiaries are not consolidated with MSIF for income tax purposes and may generate income tax expense, or benefit, and tax assets and liabilities, as a result of their ownership of certain portfolio investments. The taxable income, or loss, of the Taxable Subsidiaries may differ from their book income, or loss, due to temporary book and tax timing differences and permanent differences. The Taxable Subsidiaries are each taxed at corporate income tax rates based on their taxable income. The income tax expense, or benefit, if any, and the related tax assets and liabilities, of the Taxable Subsidiaries are reflected in MSC Income’s consolidated financial statements.

The income tax provision for MSC Income is generally composed of (i) deferred tax expense (benefit), which is primarily the result of the net activity relating to the portfolio investments held in the Taxable Subsidiaries, including changes in loss carryforwards, changes in net unrealized appreciation or depreciation and other temporary book-tax differences, and (ii) current tax expense, which is primarily the result of current U.S. federal income and state taxes relating to net currently taxable activity relating to the portfolio investments held in the Taxable Subsidiaries and excise taxes on MSC Income’s estimated undistributed taxable income. The income tax expense, or benefit, and the related tax assets and liabilities generated by the Taxable Subsidiaries, if any, are reflected in MSC Income’s Consolidated Statements of Operations. MSC Income’s provision for income taxes was comprised of the following for the three and nine months ended September 30, 2025 and 2024:

The net deferred tax liability as of September 30, 2025 was $0.8 million and the net deferred tax asset as of December 31, 2024 was $0.6 million, with the change primarily related to changes in net unrealized appreciation or depreciation, changes in loss carryforwards and other temporary book-tax differences relating to portfolio investments held by the Taxable Subsidiaries. As of September 30, 2025, for U.S. federal income tax purposes, the Taxable Subsidiaries had a net operating loss carryforward, which is not subject to expiration and will carryforward indefinitely until utilized. The Taxable Subsidiaries have net capital loss carryforwards from prior years which, if unused, will expire in various taxable years 2025 through 2029. Additionally, the Taxable Subsidiaries have interest expense limitation carryforwards which have an indefinite carryforward period.

NOTE G —SHARE REPURCHASES

Following the MSC Income Listing, the Fund entered into a share repurchase plan (the “10b5-1 Repurchase Plan”) to repurchase up to $65.0 million in the aggregate of shares of the Fund’s common stock in the open market for atwelve-month period beginning in March 2025, at times when the market price per share of the Fund’s common stock is trading below the most recently reported NAV per share of the Fund’s common stock by certain pre-determined levels (including any updates, corrections or adjustments publicly announced by the Fund to any previously announced NAV per share). The repurchases of shares of the Fund’s common stock pursuant to the 10b5-1 Repurchase Plan are intended to satisfy the conditions of Rule 10b5-1 and Rule 10b-18 under the Exchange Act and will otherwise be subject to applicable law, including Regulation M, which may prohibit purchases under certain circumstances.

The following table summarizes the shares repurchased under the 10b5-1 Repurchase Plan during the three months ended September 30, 2025.

(1)Includes broker commissions.

Main Street also entered into a share purchase plan (the “Main Street Share Purchase Plan”) to purchase up to $20.0 million in the aggregate of shares of the Fund’s common stock in the open market with terms and conditions substantially similar to the Fund’s 10b5-1 Repurchase Plan for shares of the Fund’s common stock, and daily purchases under thetwo plans, if any, are expected to be split pro rata (or as close thereto as reasonably possible) between the Fund and Main Street based on the respective plan sizes. On January 20, 2025, in connection with Main Street’s potential acquisition in excess of 3% of the Fund’s outstanding common stock as a result of any purchases of shares of the Fund’s common stock pursuant to the Main Street Share Purchase Plan or otherwise, the Fund entered into a Fund of Funds Investment Agreement with Main Street (the “Main Street Fund of Funds Agreement”). The Main Street Fund of Funds Agreement provides for the acquisition of shares of the Fund’s common stock by Main Street, and the Fund’s sale of such shares to Main Street, in a manner consistent with the requirements of Rule 12d1-4 under the 1940 Act. See Note J.4 —Related Party Transactions — Other Related Party Transactions.

NOTE H —DIVIDEND REINVESTMENT PLAN

Prior to March 6, 2025, the Fund’s dividend reinvestment plan (the “Prior DRIP”) provided for the reinvestment of dividends on behalf of its stockholders. As a result, if the Fund declared a cash dividend, its stockholders who had “opted in” to the Prior DRIP would have had their cash dividend automatically reinvested into additional shares of the Fund’s common stock. The number of shares of common stock to be issued to a stockholder under the Prior DRIP was determined by dividing the total dollar amount of the distribution payable to such stockholder by a price per share of common stock determined by the Fund’s Board of Directors or a committee thereof, in its sole discretion, that was (i) not less than the NAV per share of common stock determined in good faith by the Board of Directors or a committee thereof, in its sole discretion, within 48 hours prior to the payment of the distribution and (ii) not more than 2.5% greater than the NAV per share as of such date.

Effective as of March 6, 2025, the date of the Fund’s Board of Directors’ first declaration of a dividend or distribution on the Fund’s common stock following the MSC Income Listing, the Fund adopted an “opt out” dividend reinvestment plan (the “New DRIP” and, together with the Prior DRIP, the “DRIP”). The New DRIP provides for the reinvestment of dividends on behalf of the Fund’s registered stockholders who hold their shares with the Fund’s transfer agent and registrar, or certain brokerage firms that have elected to participate in the New DRIP, unless a stockholder has elected to receive dividends in cash. As a result, if the Fund declares a cash dividend, its registered stockholders (or stockholders holding shares through participating brokerage firms) who have not properly “opted out” of the New DRIP will have their cash dividend automatically reinvested into additional shares of the Fund’s common stock. For the avoidance of doubt, stockholders of the Fund prior to the MSC Income Listing who did not elect to “opt in” to the Prior DRIP in effect prior to the effective date of the “opt out” New DRIP were deemed to have made an election to “opt out” of the New DRIP as of the effective date of the “opt out” New DRIP and to continue to receive cash in connection with any cash dividend declared by the Fund. The share requirements of the New DRIP may be satisfied through the issuance of new shares of common stock or through open market purchases of common stock by the DRIP plan administrator. Newly issued shares will be valued based upon the final closing price of the Fund’s common stock reported on the NYSE on the trading day immediately preceding the dividend payment date for each dividend. Shares purchased in the open market to satisfy the New DRIP requirements will be valued based upon the average price of the applicable shares purchased by the DRIP plan administrator, before any associated brokerage or other costs. The DRIP is administered by the Fund’s transfer agent.

Summarized DRIP information for the nine months ended September 30, 2025 and 2024 is as follows:

NOTE I —COMMITMENTS AND CONTINGENCIES

As of September 30, 2025, MSC Income had the following outstanding commitments (in thousands):

(1)This table excludes a commitment related toone additional Other Portfolio investment for which the investment period has expired and the remaining commitment may only be drawn to pay fund expenses or for follow-on investments in existing portfolio companies. The Fund does not expect any material future capital to be called on its commitment to this investment to pay fund expenses, and based on representations from the fund manager, the Fund does not expect any further capital will be called on its commitment for follow-on investments. As a result, the Fund has excluded this commitment from this table.

MSC Income will fund its unfunded commitments from the same sources it uses to fund its investment commitments that are funded at the time they are made (which are typically through existing cash and cash equivalents and borrowings under the Credit Facilities). MSC Income follows a process to manage its liquidity and ensure that it has available capital to fund its unfunded commitments as necessary. MSC Income had no unrealized appreciation or depreciation on the outstanding unfunded commitments as of September 30, 2025.

MSC Income may, from time to time, be involved in litigation arising out of its operations in the normal course of business or otherwise. Furthermore, third parties may seek to impose liability on MSC Income in connection with the activities of its portfolio companies. While the outcome of any current legal proceedings cannot at this time be predicted with certainty, MSC Income does not expect any current matters will materially affect its financial condition or results of operations; however, there can be no assurance whether any pending or future legal proceedings will have a material adverse effect on MSC Income’s financial condition or results of operations in any future reporting period.

NOTE J —RELATED PARTY TRANSACTIONS

1. Advisory Agreements and Conditional Expense Reimbursement Waivers

On October 30, 2020, MSC Income entered into the Prior Investment Advisory Agreement with the Adviser. On January 29, 2025, in connection with the MSC Income Listing, MSC Income entered into the Advisory Agreement with the Adviser. The Advisory Agreement was approved by the affirmative vote of the holders of a majority of MSC Income’s outstanding voting securities, as defined in the 1940 Act, at the 2024 Special Meeting, and the Advisory Agreement became effective upon the MSC Income Listing. The Advisory Agreement is effective for an initialtwo-year term commencing upon the date of the MSC Income Listing on January 29, 2025.

Prior Investment Advisory Agreement

Pursuant to the Prior Investment Advisory Agreement, MSC Income paid the Adviser a base management fee and incentive fees as compensation for the services described above. The base management fee was calculated at an annual rate of 1.75% of MSC Income’s average gross assets. The term “gross assets” meant total assets of MSC Income as disclosed on MSC Income’s Consolidated Balance Sheets. “Average gross assets” were calculated based on MSC Income’s gross assets at the end of the two most recently completed calendar quarters. The base management fee was payable quarterly in arrears. The base management fee was expensed as incurred.

The incentive fee under the Prior Investment Advisory Agreement consisted oftwo parts. The first part, referred to as the subordinated incentive fee on income, was calculated and payable quarterly in arrears based on Pre-Incentive Fee Net Investment Income (as defined below) for the immediately preceding quarter. The subordinated incentive fee on income was equal to 20.0% of MSC Income’s Pre-Incentive Fee Net Investment Income for the immediately preceding quarter, expressed as a quarterly rate of return on adjusted capital at the beginning of the most recently completed calendar quarter, exceeding 1.875% (or 7.5% annualized), subject to a “catch up” feature (as described below).

For this purpose, Pre-Incentive Fee Net Investment Income meant interest income, dividend income and any other income (including any other fees such as commitment, origination, structuring, diligence and consulting fees or other fees that MSC Income receives from portfolio companies) accrued during the calendar quarter, minus MSC Income’s operating expenses for the quarter (including the management fee, expenses payable under any proposed administration agreement and any interest expense and dividends paid on any issued and outstanding preferred stock, but excluding taxes and the incentive fee). Pre-Incentive Fee Net Investment Income included, in the case of investments with a deferred interest feature (such as original issue discount debt instruments and PIK interest and zero coupon securities), accrued income that MSC Income had not yet received in cash. Pre-Incentive Fee Net Investment Income did not include any realized capital gains, realized capital losses or unrealized capital appreciation or depreciation. For purposes of this fee, adjusted capital meant cumulative gross proceeds generated from sales of MSC Income’s common stock (including proceeds from MSC Income’s DRIP) reduced for non-liquidating distributions, other than distributions of profits, paid to MSC Income’s stockholders and amounts paid for share repurchases pursuant to MSC Income’s share repurchase program. The subordinated incentive fee on income was expensed in the quarter in which it was incurred.

The calculation of the subordinated incentive fee on income for each quarter was as follows:

•No subordinated incentive fee on income was payable to the Adviser in any calendar quarter in which MSC Income’s Pre-Incentive Fee Net Investment Income did not exceed the hurdle rate of 1.875% (or 7.5% annualized) on adjusted capital;

•100% of MSC Income’s Pre-Incentive Fee Net Investment Income, if any, that exceeded the hurdle rate but was less than or equal to 2.34375% in any calendar quarter (9.375% annualized) was payable to the Adviser. This portion of the subordinated incentive fee on income was referred to as the “catch up” and was intended to provide the Adviser with an incentive fee of 20.0% on all of MSC Income’s Pre-Incentive Fee Net Investment Income as if the hurdle rate did not apply when the Pre-Incentive Fee Net Investment Income exceeded 2.34375% (9.375% annualized) in any calendar quarter; and

•For any quarter in which MSC Income’s Pre-Incentive Fee Net Investment Income exceeded 2.34375% (9.375% annualized), the subordinated incentive fee on income equaled 20.0% of the amount of MSC Income’s Pre-Incentive Fee Net Investment Income, as the hurdle rate and catch-up had been achieved.

The second part of the incentive fee, referred to as the incentive fee on capital gains, was an incentive fee on realized capital gains earned from the portfolio of MSC Income and was determined and payable in arrears as of the end of each calendar year (or upon termination of the Prior Investment Advisory Agreement). This fee equaled 20.0% of MSC Income’s incentive fee capital gains, which equaled MSC Income’s realized capital gains on a cumulative basis from inception, calculated as of the end of each calendar year, computed net of all realized capital losses and unrealized capital depreciation on a cumulative basis, less the aggregate amount of any previously paid capital gain incentive fees. At the end of each reporting period, MSC Income estimated the incentive fee on capital gains and accrued the fee based on a hypothetical liquidation of its portfolio. Therefore, the accrual included both net realized gains and net unrealized gains (the net unrealized difference between the fair value and the par value of its portfolio), if any. The incentive fee accrued pertaining to the unrealized gain was neither earned nor payable to the Adviser until such time it was realized.

Pursuant to the Prior Investment Advisory Agreement, MSC Income was required to pay or reimburse the Adviser for administrative services expenses, which included all costs and expenses related to MSC Income’s day-to-day administration and management not related to advisory services, whether such administrative services were performed by a third-party service provider or the Adviser or its affiliates (to the extent performed by the Adviser or its affiliates, the “Internal Administrative Services”). Internal Administrative Services included, but were not limited to, the cost of an Adviser’s personnel performing accounting and compliance functions and other administrative services on behalf of MSC Income.

On January 1, 2022, the Adviser assumed responsibility of certain administrative services that were previously provided for MSC Income by a third-party sub-administrator. After December 31, 2021, the Adviser continued to waive reimbursement of all Internal Administrative Services expenses, except for the cost of the services previously provided by the sub-administrator.

Advisory Agreement (post-MSC Income Listing)

Effective on the date of the MSC Income Listing and pursuant to the Advisory Agreement, MSC Income pays the Adviser a base management fee and incentive fees as compensation for investment management services under the Advisory Agreement. The base management fee is calculated at an annual rate of 1.5% of the Fund’s average total assets (including cash and cash equivalents), payable quarterly in arrears, and is calculated based on the average value of the Fund’s total assets (including cash and cash equivalents) at the end of the two most recently completed calendar quarters. The determination of total assets reflects changes in the fair value of portfolio investments reflecting both unrealized appreciation and unrealized depreciation. All or any part of base management fee not taken as to any quarter is deferred without interest and is taken in such other quarter as the Adviser shall determine, unless the Adviser expressly and in writing delivered to the Fund permanently waives receipt of such base management fee, in which event the Fund shall forever be relieved of the obligation to pay such base management fee for such quarter. The base management fee for any partial quarter is appropriately pro-rated.

Under the Advisory Agreement, the base management fee will be reduced to an annual rate of (i)1.25% of the average value of the Fund’s total assets (including cash and cash equivalents) commencing with the first full calendar quarter following the date on which the aggregate fair value of the Fund’s investments in its LMM portfolio companies falls below 20% of the Fund’s total investment portfolio at fair value and (ii)1.00% of the average value of the Fund’s total assets (including cash and cash equivalents) commencing with the first full calendar quarter following the date on which the aggregate fair value of the Fund’s investments in its LMM portfolio companies falls below 7.5% of the Fund’s total Investment Portfolio at fair value.

The incentive fee under Advisory Agreement consists of two parts: (1) a subordinated incentive fee on income and (2) an incentive fee on capital gains. The incentive fee under the Advisory Agreement for any partial quarter is appropriately pro-rated.

The first part of the incentive fee under the Advisory Agreement, referred to as the subordinated incentive fee on income, is calculated and payable quarterly in arrears based on the Fund’s pre-incentive fee net investment income for the immediately preceding quarter. The payment of the subordinated incentive fee on income is subject to pre-incentive fee net investment income for the previous quarter, expressed as a quarterly rate of return on net assets of the Fund at the beginning of the most recently completed calendar quarter, exceeding 1.5% (6.0% annualized), subject to a “catch up” feature (as described below). For this purpose, pre-incentive fee net investment income means interest income, dividend income and any other income (including any other fees, such as commitment, origination, structuring, diligence and consulting fees or other fees that the Fund receives from portfolio companies) accrued during the calendar quarter, minus the Fund’s operating expenses for the quarter (including the base management fee, administrative services expenses, the expenses payable under any other administration or similar agreement and any interest expense and dividends paid on any issued and outstanding preferred stock and any income tax expense on the Fund’s net investment income and any excise tax, but excluding any income tax expense or benefit on the Fund’s realized capital gains, realized capital losses or unrealized capital appreciation or depreciation and the incentive fee). Pre-incentive fee net investment income includes, in the case of investments with a deferred interest feature (such as original issue discount debt instruments with payment-in-kind interest and zero coupon securities), accrued income that the Fund has not yet received in cash. Pre-incentive fee net investment income does not include any realized capital gains, realized capital losses or unrealized capital appreciation or depreciation, or any income tax expense or benefit related to such items. The calculation of the subordinated incentive fee on income for each quarter is as follows:

1. No subordinated incentive fee on income is payable to the Adviser in any calendar quarter in which the Fund’s pre-incentive fee net investment income does not exceed the hurdle rate of 1.5% (or 6.0% annualized);

2.50% of the Fund’s pre-incentive fee net investment income, if any, that exceeds the hurdle rate but is less than or equal to 2.307692% in any calendar quarter (9.230769% annualized) is payable to the Adviser. This portion of the subordinated incentive fee on income is referred to as the “catch up” and is intended to provide the Adviser with an incentive fee of 17.5% on all of the Fund’s pre-incentive fee net investment income as if the hurdle rate did not apply when the pre-incentive fee net investment income exceeds 2.307692% (9.230769% annualized) in any calendar quarter; and

3. For any quarter in which the Fund’s pre-incentive fee net investment income exceeds 2.307692% (9.230769% annualized), the subordinated incentive fee on income equals 17.5% of the amount of the Fund’s pre-incentive fee net investment income, as the hurdle rate and catch-up have been achieved.

The second part of the incentive fee under the Advisory Agreement, referred to as the incentive fee on capital gains, is an incentive fee on realized capital gains earned on liquidated investments from the Fund’s Investment Portfolio, net of any income tax expense associated with such realized capital gains, and is determined and payable in arrears as of the end of each calendar year (or upon termination of the Advisory Agreement). This fee equals (a)17.5% of the Fund’s incentive fee capital gains, which equals the Fund’s realized capital gains (net of any related income tax expense) on a cumulative basis from the date of the MSC Income Listing, calculated as of the end of each calendar year thereafter (or upon termination of the Advisory Agreement), computed net of (1) all realized capital losses on a cumulative basis (net of any related income tax benefit) from the date of the MSC Income Listing, and (2) unrealized capital depreciation (net of any related income tax benefit) on a cumulative basis from the date of the MSC Income Listing, less (b) the aggregate amount of any previously paid capital gain incentive fees from the date of the MSC Income Listing. For purposes of calculating each component of the Fund’s incentive fee capital gains under the Advisory Agreement, (1) the cost basis for any investment held by the Fund as of the date of the MSC Income Listing is deemed to be the fair value for such investment as of the most recent quarter end immediately prior to the date of the MSC Income Listing and, with respect to any investment acquired by the Fund subsequent to the date of the MSC Income Listing, the cost basis equals the cost basis of such investment as reflected in the Fund’s financial statements and (2) the income tax expense or benefit associated with all investments is measured from the most recent quarter end immediately prior to the date of the MSC Income Listing through the date of any such calculation.

The following table provides a summary of MSC Income’s incurred base management fees, subordinated incentive fees on income and capital gains incentive fees for the three and nine months ended September 30, 2025 and 2024.

(1)During the three months ended September 30, 2025, the Adviser irrevocably waived $0.2 million of the subordinated incentive fees on income, and such amount is not subject to future payment. The subordinated incentive fees on income incurred before the waiver by the Adviser was $3.5 million and $8.9 million for the three and nine months ended September 30, 2025, respectively.

Under the Advisory Agreement, the waivers under the Prior Investment Advisory Agreement of Internal Administrative Services expenses, except for the cost of the services previously provided by the former sub-administrator, were memorialized as a quarterly cap on the Fund’s obligation to reimburse the Adviser for “Internal Administrative Expenses.”MSC Income is not required to reimburse the Adviser for Internal Administrative Expenses in an amount that exceeds on a quarterly basis the product obtained by multiplying (x) the value of MSC Income’s total assets at the end of each calendar quarter by (y) the applicable “Annual Basis Point Rate” set forth in the below table:

The following table provides a summary of MSC Income’s incurred Internal Administrative Expenses (before and after waivers) for the three and nine months ended September 30, 2025 and 2024.

(1)Waived Internal Administrative Services expenses are permanently waived and are not subject to future reimbursement.

2. Indemnification

The Prior Investment Advisory Agreement and the Advisory Agreement provide that the Adviser, any sub-adviser and their respective officers, directors, managers, partners, shareholders, members (and their shareholders or members, including the owners of their shareholders or members), agents, employees, controlling persons and any other person or entity affiliated with or acting on behalf of the Adviser or any sub-adviser, as applicable (each an “Indemnified Party” and, collectively, the “Indemnified Parties”) will not be liable to MSC Income for any action taken or omitted to be taken by the Adviser or any sub-adviser in connection with the performance of any of their duties or obligations as an investment adviser of the Fund (except to the extent specified in Section 36(b) of the 1940 Act concerning loss resulting from a breach of fiduciary duty (as the same is finally determined by judicial proceedings) with respect to the receipt of compensation for services), and that MSC Income will indemnify, defend and protect Indemnified Parties and hold them harmless from and against all losses, damages, liabilities, costs and expenses (including reasonable attorneys’ fees and amounts reasonably paid in settlement) incurred by the Indemnified Parties in connection with the performance of their duties as an investment adviser of the Fund, to the extent such losses, damages, liabilities, costs and expenses are not fully reimbursed by insurance, and to the extent that such indemnification would not be inconsistent with the Maryland General Corporation Law, the 1940 Act, the Fund’s charter and other applicable law if, among other things, (i) the Indemnified Party has determined, in good faith, that the course of conduct which caused the loss or liability was in the best interests of the Fund, (ii) the Indemnified Party was acting on behalf of or performing services for the Fund, (iii) such liability or loss was not the result of negligence, willful misfeasance, bad faith, or misconduct by the Indemnified Party and (iv) such indemnification or agreement to hold harmless is recoverable only out of the Fund’s net assets and not from stockholders.

3. Co-Investment

In the ordinary course of business, MSC Income enters into transactions with other parties that may be considered related party transactions. MSC Income has implemented certain policies and procedures, both written and unwritten, to ensure that it does not engage in any prohibited transactions with any persons affiliated with MSC Income. If such affiliations are found to exist, MSC Income seeks the Board of Directors and/or appropriate Board of Directors committee review and approval for such transactions and otherwise comply with, or seek, orders for exemptive relief from the SEC, as appropriate.

MSC Income has received an exemptive order from the SEC permitting co-investments among MSC Income, Main Street and other advisory clients of the Adviser in certain negotiated transactions where co-investing would otherwise be prohibited under the 1940 Act. MSC Income has made co-investments, and in the future intends to continue to make co-investments with Main Street and other advisory clients of the Adviser, in accordance with the conditions of the order. The order requires, among other things, that the Adviser and Main Street consider whether each such investment opportunity is appropriate for MSC Income, Main Street and the other advisory clients of the Adviser, as applicable, and if it is appropriate, to propose an allocation of the investment opportunity between such parties. Because the Adviser is wholly-owned by Main Street and is not managing MSC Income’s investment activities as its sole activity, this may provide the Adviser an incentive to allocate opportunities to other participating advisory clients instead of MSC Income. However, both MSC Income and the Adviser have policies and procedures in place to manage this conflict, including approval of investment allocations and oversight of co-investments by the independent members of the Board of Directors. Additional information regarding the operation of the co-investment program is set forth in the order granting exemptive relief, which may be reviewed on the SEC’s website at www.sec.gov. In addition to the co-investment program described above, MSC Income also co-invests in certain investment transactions where price is the only negotiated point by MSC Income and its affiliates.

4. Other Related Party Transactions

The following table summarizes Main Street’s purchases of shares of MSC Income’s common stock during the three months ended September 30, 2025, pursuant to the Main Street Share Purchase Plan.

(1)Includes broker commissions.

As of September 30, 2025, Main Street owned 1,433,573 shares of MSC Income’s common stock. In addition, certain of Main Street’s officers and employees own shares of MSC Income and therefore have direct pecuniary interests in MSC Income.

NOTE K —SUBSEQUENT EVENTS

The Fund’s management has evaluated subsequent events through the date of issuance of the consolidated financial statements, and identified the following to report:

In November 2025, MSC Income declared a regular quarterly dividend of $0.35 per share and a supplemental quarterly dividend of $0.01 per share, both payable on January 30, 2026 to stockholders of record as of December 31, 2025.

Since September 30, 2025 through November 13, 2025, the Fund repurchased 357,304 shares at an average price of $12.69 (including broker commissions), as part of the Fund’s 10b5-1 Repurchase Plan.