Exhibit 4.1

Execution Version

NINTH AMENDMENT TO INDENTURE

NINTH AMENDMENT TO INDENTURE, dated as of March 3, 2026 (this “Amendment”) to Indenture, dated as of February 8, 2019 (as amended by that certain First Amendment thereto, dated as of June 14, 2019, that certain Second Amendment thereto, dated as of November 21, 2019, that certain Third Amendment thereto, dated as of August 31, 2020, that certain Fourth Amendment thereto, dated as of March 18, 2021, that certain Fifth Amendment thereto, dated as of January 20, 2023, that certain Sixth Amendment thereto, dated as of March 15, 2023, that certain Seventh Amendment thereto, dated as of May 22, 2025, and that certain Eighth Amendment thereto, dated as of November 14, 2025, and as the same may be further amended, restated, supplemented or otherwise modified and in effect from time to time, the “Indenture”), among Stack Infrastructure Issuer, LLC, a Delaware limited liability company (the “Issuer”), 394 Pacific DCP ABS, LLC, a Delaware limited liability company (“Portland I”), SI ATL01A ABS, LLC (f/k/a SI ATL01 ABS, LLC), a Delaware limited liability company (“Atlanta I”), SI CHI01A ABS, LLC (f/k/a CHI01 ABS, LLC), a Delaware limited liability company (“Chicago I”), SI DFW01A ABS, LLC (f/k/a SI DFW01 ABS, LLC), a Delaware limited liability company (“Dallas I”), SI POR02 ABS, LLC (f/k/a SI POR01 ABS, LLC), a Delaware limited liability company (“Portland II”), SI SVY01A-B ABS, LLC (f/k/a SI SVY01-02 ABS, LLC), a Delaware limited liability company (“Silicon Valley I”), SI NAL01A ABS, LLC (f/k/a SI NAL01 ABS, LLC), a Delaware limited liability company (“New Albany I”), SI NVA01 ABS, LLC, a Delaware limited liability company (“Northern Virginia I”) and SI DFW01B, LLC (f/k/a SI DFW02, LLC), a Delaware limited liability company (“Dallas II” and, together with Portland I, Atlanta I, Chicago I, Dallas I, Portland II, Silicon Valley I, New Albany I and Northern Virginia I, the “Closing Date Asset Entities” and together with any entity that becomes a party to the Indenture after the date hereof as an “Additional Asset Entity”, the “Asset Entities”; the Asset Entities and the Issuer, collectively, the “Obligors”), and Wilmington Trust, National Association, as indenture trustee and not in its individual capacity and any successor thereto in such capacity (the “Indenture Trustee”).

R E C I T A L S

WHEREAS, the Issuer, the Closing Date Asset Entities and the Indenture Trustee are parties to the Existing Indenture;

WHEREAS, the Issuer desires to enter into, execute and deliver this Amendment in compliance with the terms of the Existing Indenture;

WHEREAS, Section 13.01(xi) of the Existing Indenture permits the Issuer and the Indenture Trustee, when authorized by an Issuer Order, to supplement or amend the terms of the Existing Indenture for any purpose not enumerated in Sections 13.01(i) through (x), without the consent of the Noteholders so long as (x) any such amendment (1) will not adversely affect in any material respect the interests of any Noteholder (as evidenced by a Rating Agency Confirmation) and (2) will not diminish any rights or remedies or increase any liabilities or obligations of the Servicer under the Indenture, under the Servicing Agreement or under any other Transaction Document without the consent of the Servicer, and (y) in connection with any supplement or

amendment for purposes described in Section 13.01(iii), (iv), (v), (vii), (x) or (xi), the Issuer receives an Opinion of Counsel (which opinion may contain similar assumptions and qualifications as are contained in the Opinion of Counsel with respect to the tax treatment of the Notes delivered on the Initial Closing Date) to the effect that such supplement or amendment will not (1) cause any of the Notes to be deemed to have been exchanged for a new debt instrument pursuant to Treasury Regulations § 1.1001-3, (2) cause the Issuer to be taxable as other than a partnership or disregarded entity for U.S. federal income tax purposes or (3) cause any of the Notes to be characterized as other than indebtedness for U.S. federal income tax purposes;

WHEREAS, Section 13.02 of the Existing Indenture permits the Issuer and the Indenture Trustee, when authorized by an Issuer Order, with a prior direction of Noteholders representing more than 50.0% of the Voting Rights of each Class of Notes adversely affected thereby and without prior notice to any other Noteholder, to amend, supplement or modify the Indenture or waive compliance by the Issuer with any provision of the Existing Indenture so long as such amendment, supplement, modification or waiver is not enumerated in Sections 13.02(i) through (ix) (in which case such amendment, supplement, modification or waiver would require the consent of the Holder of each Note affected thereby and with respect to clause (viii), the consent of the Servicer);

WHEREAS, the Issuer and the Indenture Trustee, desire to enter into this Amendment as an amendment to the Existing Indenture in compliance with the terms thereof;

WHEREAS, this Amendment constitutes an Indenture Supplement (as defined in the Indenture);

WHEREAS, a Rating Agency Confirmation has been received with respect to this Amendment and the Issuer has received an Opinion of Counsel (which opinion may contain similar assumptions and qualifications as are contained in the Opinion of Counsel with respect to the tax treatment of the Notes delivered on the Initial Closing Date) to the effect that this Amendment will not (1) cause any of the Notes to be deemed to have been exchanged for a new debt instrument pursuant to Treasury Regulations § 1.1001-3, (2) cause the Issuer to be taxable as other than a partnership or disregarded entity for U.S. federal income tax purposes or (3) cause any of the Notes to be characterized as other than indebtedness for U.S. federal income tax purposes;

WHEREAS, in accordance with Section 13.01(xi) and Section 13.02 of the Existing Indenture, the Issuer and the Indenture Trustee, by their signatures below, have agreed to the entry into this Amendment, and each of the Holders of the Notes issued on or after the date hereof are deemed to have consented to the related Ninth Amendment Springing Amendments (which amendments shall take effect on or after the Ninth Amendment Springing Amendment Effective Date); and

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Issuer and the Indenture Trustee hereby agree as follows:

A G R E E M E N T S

SECTION 1.Defined Terms. Capitalized terms used and not otherwise defined herein (including the preamble and recitals hereto) shall have the meanings specified in the Indenture, as amended hereby.

SECTION 2.Amendments to the Indenture.

(a) As of the date hereof, the Indenture is hereby amended to delete the stricken text (indicated textually in the same manner as the following example: stricken text) and to add the bold and double-underlined text (indicated textually in the same manner as the following example: bold and double-underlined text) as set forth in the conformed Indenture attached as Exhibit A hereto (the “Amended Indenture”).

(b) Except as expressly set forth in this Amendment, the Exhibits and Schedules to the Indenture shall be the Exhibits and Schedules to the Amended Indenture and on and after the date hereof, unless otherwise specified, any reference to “Indenture” in the Exhibits and/or Schedules and/or Transaction Documents included in the Indenture shall be a reference to the Indenture, as amended, amended and restated, supplemented or otherwise modified from time to time.

SECTION 3.Reference to and Effect on the Indenture; Ratification.

(a) Upon the effectiveness hereof, on and after the date hereof, each reference in the Indenture to “this Indenture”, “hereunder”, “hereof” or words of like import referring to the Indenture, and each reference in any other agreement to “the Indenture”, “thereunder”, “thereof” or words of like import referring to the Indenture, shall mean and be a reference to the Indenture as amended hereby.

(b) Except as specifically amended above, the Existing Indenture is and shall continue to be in full force and effect and is hereby ratified and confirmed in all respects.

(c) The execution, delivery and effectiveness of this Amendment shall not, except as expressly provided herein, operate as a waiver of any right, power or remedy of any party hereto under the Indenture, or constitute a waiver of any provision of any other agreement.

SECTION 4.Effectiveness. This Amendment shall be effective upon delivery of executed signature pages by all parties hereto. The Obligors and the Indenture Trustee agree and acknowledge that the Rating Agency Confirmation has been satisfied with respect to this Amendment.

SECTION 5.Execution in Counterparts; Electronic Execution. This Amendment may be executed in any number of counterparts, each of which so executed shall be deemed to be an original, but all such respective counterparts shall together constitute but one and the same instrument. Delivery of an executed counterpart of this Amendment in Portable Document Format (PDF) or by facsimile shall be effective as delivery of a manually executed counterpart of this Amendment. The words “execution,” “execute”, “signed,” “signature,” and words of like import in or related to any document to be signed in connection with this Amendment and the transactions contemplated hereby (including without limitation amendments, waivers and consents) shall be deemed to include electronic signatures, the electronic matching of assignment terms and contract formations on electronic platforms approved by the Indenture Trustee, or the keeping of records in electronic form, each of which shall be of the same legal effect, validity or enforceability as a manually executed signature or the use of a paper-based recordkeeping system,

as the case may be, to the extent and as provided for in any applicable law, including the Federal Electronic Signatures in Global and National Commerce Act, the New York State Electronic Signatures and Records Act, or any other similar state laws based on the Uniform Electronic Transactions Act.

SECTION 6.Governing Law. THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

SECTION 7.Captions. The captions in this Amendment are for convenience of reference only and shall not affect the construction hereof or thereof.

SECTION 8.Limitation of Liability of Indenture Trustee. This Amendment is executed by Wilmington Trust, National Association, not in its individual capacity, but solely in its capacity as Indenture Trustee, and as such Wilmington Trust, National Association shall incur no personal liability in connection herewith.

[Signature page follows]

IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be executed by their respective officers thereunto duly authorized, as of the date first above written.

STACK INFRASTRUCTURE ISSUER, LLC

Blue Owl Digital Infrastructure Trust 8-K