Filed pursuant to Rule 424(b)(3)

File No. 333-278477

APOLLO DEBT SOLUTIONS BDC

SUPPLEMENT NO. 5 DATED AUGUST 10, 2026

TO THE PROSPECTUS DATED APRIL 16, 2026

This prospectus supplement (“Supplement”) is part of and should be read in conjunction with the prospectus of Apollo Debt Solutions BDC (the “Company”), dated April 16, 2026 (as supplemented to date, the “Prospectus”). Unless otherwise defined herein, capitalized terms used in this Supplement shall have the same meanings as in the Prospectus.

The purposes of this Supplement are:

Updates to Prospectus

The following replaces the paragraph under “May I reinvest my cash distributions in additional Common Shares?” in the Prospectus Summary section of the Prospectus and all similar disclosure in the Prospectus:

A: Yes. We have adopted a distribution reinvestment plan whereby shareholders (other than Alabama, Arkansas, California, Idaho, Kansas, Kentucky, Maine, Maryland, Massachusetts, Minnesota, Nebraska, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Tennessee, Texas, Vermont and Washington investors and clients of certain participating brokers that do not permit automatic enrollment in our distribution reinvestment plan) will have their cash distributions automatically reinvested in additional Common Shares unless they elect to receive their distributions in cash. Alabama, Arkansas, California, Idaho, Kansas, Kentucky, Maine, Maryland, Massachusetts, Minnesota, Nebraska, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Tennessee, Texas, Vermont and Washington investors and clients of certain participating brokers that do not permit automatic enrollment in our distribution reinvestment plan will automatically receive their distributions in cash unless they elect to have their cash distributions reinvested in additional Common Shares. If you participate in our distribution reinvestment plan, the cash distributions attributable to the class of Common Shares that you own will be automatically invested in additional Common Shares. The purchase price for Common Shares purchased under our distribution reinvestment plan will be equal to the most recent NAV per share for such Common Shares at the time the distribution is payable. Shareholders will not pay upfront selling commissions when purchasing Common Shares under our distribution reinvestment plan; however, all Common Shares, including those purchased under our distribution reinvestment plan, will be subject to ongoing shareholder servicing and/or distribution fees. Participants may terminate their participation in the distribution reinvestment plan by providing written notice to the Plan Administrator (defined below) five business days in advance of the first calendar day of the next month in order for a shareholder’s termination to be effective for such month. See “Description of Our Common Shares” and “Distribution Reinvestment Plan.”

The following replaces the second paragraph of the “Distribution Reinvestment Plan” section of the Prospectus and all similar disclosure in the Prospectus:

No action is required on the part of a registered shareholder to have his, her or its cash dividend or other distribution reinvested in our Common Shares, except shareholders in certain states. Shareholders can elect to “opt out” of the Fund’s distribution reinvestment plan in their subscription agreements (other than Alabama, Arkansas, California, Idaho, Kansas, Kentucky, Maine, Maryland, Massachusetts, Minnesota, Nebraska, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Tennessee, Texas, Vermont and Washington investors and clients of certain participating brokers that do not permit automatic enrollment in our distribution reinvestment plan and must affirmatively opt in to participate in the plan). Alabama, Arkansas, California, Idaho, Kansas, Kentucky, Maine, Maryland, Massachusetts, Minnesota, Nebraska, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Tennessee, Texas, Vermont and Washington investors and clients of certain participating brokers that do not permit automatic enrollment in our distribution reinvestment plan will automatically receive their distributions in cash unless they elect to have their cash distributions reinvested in additional Common Shares.

The following replaces the second sentence in the “Distribution Method” section in “Appendix A: Form of Subscription Agreement”:

You are automatically enrolled in our Distribution Reinvestment Plan, unless you are a resident of ALABAMA, ARKANSAS, CALIFORNIA, IDAHO, KANSAS, KENTUCKY, MAINE, MARYLAND, MASSACHUSETTS, MINNESOTA, NEBRASKA, NEW JERSEY, NORTH CAROLINA, OHIO, OKLAHOMA, OREGON, TENNESSEE, TEXAS, VERMONT OR WASHINGTON.

The following replaces the sixth bullet point in the “Distribution Method” section in “Appendix A: Form of Subscription Agreement”:

If you ARE a resident of Alabama, Arkansas, California, Idaho, Kansas, Kentucky, Maine, Maryland, Massachusetts, Minnesota, Nebraska, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Tennessee, Texas, Vermont or Washington, you are not automatically enrolled in the Distribution Reinvestment Plan. Please check here if you wish to enroll in the Distribution Reinvestment Plan. You will automatically receive cash distributions unless you elect to enroll in the Distribution Reinvestment Plan.

2026 Debt Securitization

On August 6, 2026 (the “Closing Date”), the Company completed a $514,900,000 term debt securitization (the “2026 Debt Securitization”). Term debt securitizations are also known as collateralized loan obligations and are a form of secured financing incurred by a subsidiary of the Company, which is consolidated by the Company and subject to the Company’s overall asset coverage requirements.

On the Closing Date and in connection with the 2026 Debt Securitization, ADL CLO 3 LLC (the “CLO Issuer”), an indirect, wholly-owned, consolidated subsidiary of the Company, entered into (i) a purchase agreement (the “CLO Purchase Agreement”) with Citigroup Global Markets Inc., as initial purchaser (the “Initial Purchaser”) and (ii) a placement agreement (the “CLO Placement Agreement”) with Citigroup Global Markets Inc., as a placement agent and Apollo Global Securities, LLC, as a placement agent (collectively, the “Placement Agents”), pursuant to which the Initial Purchaser and the Placement Agents agreed to purchase or place, as applicable, certain of the notes issued by the CLO Issuer as part of the 2026 Debt Securitization pursuant to an indenture by and between the CLO Issuer and Western Alliance Trust Company, N.A., as collateral trustee (the “CLO Indenture”).

The notes issued as part of the 2026 Debt Securitization consist of $248,700,000 of AAA(sf) Class A-1a Senior Secured Floating Rate Notes due 2038, which bear interest at the three-month secured overnight financing rate published by the Federal Reserve Bank of New York (“SOFR”) plus 1.50% (the “Class A-1a Notes”); $20,600,000 of AAA(sf) Class A-1b Senior Secured Floating Rate Notes due 2038, which bear interest at the three-month SOFR plus 1.70% (the “Class A-1b Notes”); $30,900,000 of AA(sf) Class A-2 Senior Secured Floating Rate Notes due 2038, which bear interest at the three-month SOFR plus 1.85% (the “Class A-2 Notes”); $41,200,000 of A(sf) Class B Secured Deferrable Floating Rate Notes due 2038, which bear interest at the three-month SOFR plus 2.25% (the “Class B Notes”); $30,900,000 of BBB-(sf) Class C Secured Deferrable Floating Rate Notes due 2038, which bear interest at the three-month SOFR plus 3.60% (the “Class C Notes” and together with the Class A-1a Notes, the Class A-1b Notes, the Class A-2 Notes and the Class B Notes, the “Secured Notes”). Additionally, on the Closing Date, the CLO Issuer issued $92,600,000 of Subordinated Notes due 2126 (the “Subordinated Notes”), which do not bear interest. The Secured Notes together with the Subordinated Notes are collectively referred to herein as the “Notes”.

Additionally, the CLO Issuer incurred certain loans as part of the 2026 Debt Securitization, consisting of $50,000,000 of AAA(sf) Class A-1a Loans maturing 2038, which bear interest at the three-month SOFR plus 1.50% (the “Class A-1a Loans” and the Class A-1a Loans together with the Secured Notes, the “Secured Debt” and the Secured Debt together with the Subordinated Notes, the “Debt”) incurred by the CLO Issuer on the Closing Date. The Class A-1a Loans were incurred pursuant to a Class A-1a Credit Agreement among the CLO Issuer, as borrower, Western Alliance Trust Company, N.A., as loan agent and collateral trustee and the lenders party thereto (the “Class A-1a Credit Agreement”).

The 2026 Debt Securitization is backed by a diversified portfolio consisting primarily of first-lien commercial loans. The Secured Debt is scheduled to mature on July 15, 2038 and the Subordinated Notes are scheduled to mature on July 15, 2126; however, the Debt may be redeemed by the CLO Issuer, at the direction of ADL CLO 3 Depositor LLC (the “CLO Retention Holder”), a wholly-owned, consolidated subsidiary of the Company, as owner of a majority of the Subordinated Notes, on any business day on or after July 15, 2028. The CLO Retention Holder acts as retention holder in connection with the 2026 Debt Securitization for the purposes of satisfying certain U.S. regulations requiring sponsors of securitization transactions to retain exposure to the performance of the securitized assets and as such is required to retain a portion of the Subordinated Notes. The Company, through the CLO Retention Holder, has retained a portion of the Class A-2 Notes and 100% of the Class B Notes, the Class C Notes and the Subordinated Notes issued in the 2026 Debt Securitization.

The CLO Issuer intends to use the proceeds from the 2026 Debt Securitization to, among other things, purchase certain loans (“Collateral Obligations”) from time to time on and after the Closing Date from the Company pursuant to a master loan sale agreement entered into on the Closing Date (the “CLO Loan Sale Agreement”) among the Company, the CLO Retention Holder and the CLO Issuer. Under the terms of the CLO Loan Sale Agreement that provide for the sale of Collateral Obligations to the CLO Issuer, the Company will transfer to the CLO Retention Holder, and the CLO Retention Holder will transfer to the CLO Issuer, a portion of its ownership interest in the Collateral Obligations securing the 2026 Debt Securitization for the purchase price and other consideration set forth in the CLO Loan Sale Agreement from time to time on and after the Closing Date. Following these transfers, the CLO Issuer, and not the CLO Retention Holder or the Company, will hold all of the ownership interest in such loans and participations. The Company made customary representations, warranties and covenants in the CLO Loan Sale Agreement.

The Secured Debt is the secured obligation of the CLO Issuer, the Subordinated Notes are the unsecured obligations of the CLO Issuer, and the CLO Indenture and the Class A-1a Credit Agreement governing the Debt include customary covenants and events of default. The Debt has not been, and will not be, registered under the Securities Act of 1933, as amended, or any state securities or “blue sky” laws and may not be offered or sold in the United States absent registration with the Securities and Exchange Commission or an applicable exemption from registration.

The Company serves as collateral manager to the CLO Issuer under a collateral management agreement entered into on the Closing Date (the “CLO Collateral Management Agreement”). Pursuant to the CLO Collateral Management Agreement, so long as the Company is the collateral manager, the collateral management fee will equal 0.0% per annum of the fee basis amount.

The above descriptions of the documentation related to the 2026 Debt Securitization and other arrangements entered into on the Closing Date do not purport to be complete and are qualified in their entirety by reference to the underlying agreements, including the CLO Purchase Agreement, CLO Placement Agreement, the CLO Indenture, Class A-1a Credit Agreement, the CLO Collateral Management Agreement and the CLO Loan Sale Agreement, which are attached as exhibits to the registration statement of which this Prospectus is a part.

Quarterly Report on Form 10-Q for the Quarter Ended June 30, 2026

On August 10, 2026, we filed our Quarterly Report on Form 10-Q for the quarter ended June 30, 2026 with the Securities and Exchange Commission. The report (without exhibits) is attached to this Supplement.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

For the quarterly period ended June 30, 2026

OR

For the transition period from ________ to ___________

Commission File Number: 814-01424

APOLLO DEBT SOLUTIONS BDC

(Exact name of Registrant as specified in its charter)

Registrant’s telephone number, including area code: (212) 515-3200

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.

(Do not check if a smaller reporting company)

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of August 10, 2026, there was no established public market for the Registrant’s common shares of beneficial interest ("Common Shares").

The number of shares of the Registrant’s Common Shares, $0.01 par value per share, outstanding as of August 10, 2026 was 120,749,477 Class S Common Shares, 1,718,732 Class D Common Shares and 468,544,335 Class I Common Shares. Common Shares outstanding exclude August 1, 2026 subscriptions since the issuance price is not yet finalized at this time.

APOLLO DEBT SOLUTIONS BDC

Table of Contents

PART I. FINANCIAL INFORMATION

In this report, the terms the "Company," "ADS," "we," "us" or "our" refer to Apollo Debt Solutions BDC unless the context specifically states otherwise.

Item 1. Consolidated Financial Statements