Subject to Completion Preliminary Prospectus Supplement dated July 28, 2021 PROSPECTUS SUPPLEMENT (To Prospectus dated June 3, 2021) 12,500,000 Shares nd it is not soliciting an offer to buy Common Stock We are offering for sale 12,500,000 shares of our common stock. Ares Capital Corporation is a specialty finance company that is a closed-end, non-diversified management investment company incorporated in Maryland. We have elected to be regulated as a business development company under the Investment Company Act of 1940, as amended. Our investment objective is to generate both current income and capital appreciation through debt and equity investments. We invest primarily in first lien senior secured loans (including “unitranche” loans, which are loans that combine both senior and subordinated debt, generally in a first lien position), and second lien senior secured loans. In addition to senior secured loans, we also invest in subordinated debt (sometimes referred to as mezzanine debt), which in some cases includes an equity component, and preferred equity. To a lesser extent, we also make common equity investments. We are externally managed by our investment adviser, Ares Capital Management LLC, a subsidiary of Ares Management Corporation, a publicly traded, leading global alternative investment manager. Ares Operations LLC, a subsidiary of Ares Management Corporation, provides certain administrative and other services necessary for us to operate. Our common stock is traded on The NASDAQ Global Select Market under the symbol “ARCC.” On July 27, 2021, the official close price of our common stock on The NASDAQ Global Select Market was $20.12 per share. The net asset value per share of our common stock at June 30, 2021 (the last date prior to the date of this prospectus supplement on which we determined net asset value) was $18.16. Investing in our common stock involves risks. Before making a decision to invest in our common stock, you should carefully consider the matters discussed under “Risk Factors” beginning on page 15 of the accompanying prospectus and the matters discussed in the documents incorporated or deemed to be incorporated by reference in this prospectus supplement and the accompanying prospectus. This prospectus supplement and the accompanying prospectus concisely provide important information about us that you should know before investing in our common stock. We may also authorize one or more free writing prospectuses to be provided to you in connection with this offering (such free writing prospectus and this prospectus supplement collectively referred to hereinafter as the “prospectus supplement”). Please read this prospectus supplement and the accompanying prospectus, and the documents incorporated by reference, before you invest and keep them for future reference. We file annual, quarterly and current reports, proxy statements and other information with the Securities and Exchange Commission (the “SEC”). This information is available free of charge by calling us collect at (310) 201-4200, by sending an e-mail to us at [email protected] or on our website at www.arescapitalcorp.com. The SEC also maintains a website at www.sec.gov that contains such information. The information on the websites referred to herein is not incorporated by reference into this prospectus supplement or the accompanying prospectus. The underwriters have agreed to purchase the common stock from us at a price of $ per share, which will result in $ of proceeds to us before expenses. The underwriters may offer the shares of common stock from time to time for sale in one or more transactions on The NASDAQ Global Select Market, in the over-the-counter market, through negotiated transactions or otherwise at market prices prevailing at the time of sale, at prices related to prevailing market prices or at negotiated prices. The underwriters may also purchase up to an additional 1,875,000 shares from us at the price per share set forth above within 30 days of the date of this prospectus supplement. Neither the SEC nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense. The shares will be ready for delivery on or about , 2021. Morgan Stanley BofA Securities Wells Fargo Securities Goldman Sachs & J.P. Morgan RBC Capital UBS Investment Keefe, Bruyette & Raymond James Co. LLC Markets Bank Woods A Stifel Company Compass Point Janney Montgomery Scott JMP Securities Oppenheimer & Co. The date of this prospectus supplement is July , 2021. these securities in any jurisdiction where the offer or sale is not permitted. The information in this prospectus supplement is not complete and may be changed. This prospectus supplement is not an offer to sell these securities a You should rely only on the information contained in this prospectus supplement and the accompanying prospectus, the documents incorporated by reference in this prospectus supplement and the accompanying prospectus, or any other information to which we have referred you. We have not, and the underwriters have not, authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not, and the underwriters are not, making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement and the accompanying prospectus is accurate only as of the date on the front cover of this prospectus supplement or the accompanying prospectus, as applicable. Our business, financial condition, results of operations and prospects may have changed since that date. This prospectus supplement may add, update or change information contained in the accompanying prospectus. If information in this prospectus supplement is inconsistent with the accompanying prospectus, this prospectus supplement will apply and will supersede that information in the accompanying prospectus. Prospectus Supplement TABLE OF CONTENTS Page Forward-Looking Statements .................................................. S-1 The Company ............................................................ S-3 Fees and Expenses ......................................................... S-6 Use of Proceeds ........................................................... S-10 Capitalization ............................................................. S-11 Price Range of Common Stock and Distributions ................................... S-12 Underwriting ............................................................. S-13 Legal Matters ............................................................. S-18 Incorporation by Reference ................................................... S-19 Prospectus TABLE OF CONTENTS Page Prospectus Summary ........................................................ 1 The Company ............................................................. 1 Offerings ................................................................ 4 Fees and Expenses .......................................................... 7 Financial Highlights ........................................................ 11 Risk Factors .............................................................. 15 Forward-Looking Statements .................................................. 17 Use of Proceeds ........................................................... 19 Price Range of Common Stock and Distributions .................................... 21 Management’s Discussion and Analysis of Financial Condition and Results of Operations ....... 23 Senior Securities ........................................................... 24 Business ................................................................. 25 Portfolio Companies ........................................................ 26 Management .............................................................. 64 Certain Relationships and Related Transactions ..................................... 68 Control Persons and Principal Stockholders ........................................ 69 Determination of Net Asset Value ............................................... 71 S-i Page Dividend Reinvestment Plan ................................................... 72 Certain Material U.S. Federal Income Tax Considerations .............................. 74 Description of Securities ..................................................... 83 Description of Our Capital Stock ............................................... 84 Description of Our Preferred Stock .............................................. 91 Description of Our Subscription Rights ........................................... 92 Description of Our Warrants .................................................. 94 Description of Our Debt Securities .............................................. 96 Description of Our Units ..................................................... 107 Sales of Common Stock Below Net Asset Value ..................................... 108 Issuance of Warrants or Securities to Subscribe For or Convertible Into Shares of Our Common Stock ................................................................. 113 Regulation ............................................................... 114 Custodian, Transfer and Dividend Paying Agent and Registrar ........................... 121 Brokerage Allocation