UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. __)*

Algoma Steel Group Inc.

(Name of Issuer)

Common Shares, without par value

(Title of Class of Securities)

015658107

(CUSIP Number)

Michael P. McNamara

Executive Vice President

Zekelman Industries, Inc.

227 West Monroe Street, Suite 2600

Chicago, Illinois 60606

(312) 275-1600

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

Copies to:

John Harrington

Samuel Toth

BakerHostetler

127 Public Square, Suite 2000

Cleveland, Ohio 44114

(216) 621-0200

July 25, 2024

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. ☐

NOTE: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

EXPLANATORY NOTE

Item 1. Security and Issuer.

This Schedule 13D relates to Common Shares, without par value, of Algoma Steel Group Inc., a British Columbia corporation (the “Issuer”), whose principal executive office is located at 105 West Street Sault Ste. Marie, Ontario P6A 7B4, Canada.

Item 2. Identity and Background.

Item 3. Source and Amount of Funds or Other Considerations.

The information set forth in Items 4 and 5 hereof is hereby incorporated by reference into this Item 3, as applicable. All Common Shares of the Issuer beneficially owned by the Reporting Persons were acquired with the working capital of the Reporting Persons in open market purchases. The aggregate purchase price of all the Common Shares beneficially owned by the Reporting Persons was approximately $42,075,380, excluding brokerage commissions.

Item 4. Purpose of Transaction.

The Reporting Persons are customers of the Issuer and acquired the Common Shares for investment purposes. Depending upon overall market conditions, other investment opportunities available to the Reporting Persons, the availability of Common Shares at prices that would make the purchase or sale of the Common Shares desirable, and the Reporting Persons’ business relationship with the Issuer, the Reporting Persons may endeavor to increase or decrease their position in the Issuer through, among other things, the purchase or sale of Common Shares on the open market or in private transactions or otherwise, on such terms and at such times as the Reporting Persons may deem advisable.

Neither the Reporting Persons nor, to the knowledge of the Reporting Persons, any of the other persons identified in Item 2(a) have any current plans or proposals which would relate to or result in any of the matters set forth in subparagraphs (a) – (j) of Item 4 of Schedule 13D except as set forth herein or such as would occur upon or in

connection with completion of, or following, any of the actions discussed herein. The Reporting Persons intend to review their investment in the Issuer on a continuing basis. Depending on various factors including, without limitation, the Issuer’s financial position and investment strategy, the price levels of the Common Shares, conditions in the securities markets and general economic and industry conditions, and the Reporting’s business relationship with the Issuer, the Reporting Persons may in the future take such actions with respect to their investment in the Issuer as it deems appropriate including, without limitation, engaging in communications with management and the Board of Directors of the Issuer, engaging in discussions with stockholders of the Issuer or other third parties about the Issuer and the Reporting Persons’ investment, including potential business combinations, dispositions or other transactions involving the Issuer or certain of its businesses, making recommendations or proposals to the Issuer concerning changes to the capitalization, ownership structure, board structure (including board composition), or suggestions for improving the Issuer’s financial and/or operational performance, purchasing additional Common Shares, selling some or all of their Common Shares, engaging in short selling of or any hedging or similar transaction with respect to the Common Shares, including swaps and other derivative instruments, or changing their intention with respect to any and all matters referred to in Item 4.

Item 5. Interest in Securities of the Issuer.

This Schedule 13D relates to the Common Shares held directly by Atlas Tube, which is an indirect operating subsidiary of Zekelman Industries. Because Zekelman Industries indirectly owns all the voting equity of Atlas Tube, Zekelman Industries may be deemed to beneficially own all such Common Shares held directly by Atlas Tube.

None of the natural persons identified in Item 2(a) beneficially own any Common Shares of the Issuer, except as otherwise indicated on Schedule A, which is incorporated herein by reference.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

Each Reporting Person is a party to that certain Joint Filing Agreement, which is attached hereto as Exhibit 1 and incorporated herein by reference. Except for the Joint Filing Agreement, there are no contracts, arrangements, understandings or relationships (legal or otherwise) among the persons identified in Item 2 or between such persons and any other person, with respect to any securities of Issuer.

Item 7. Material to Be Filed as Exhibits.

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, such person certifies that the information set forth in this statement is true, complete and correct.

Dated: July 31, 2024

Schedule A

Executive Officers and Directors of Zekelman Industries

Executive Officers and Directors of Atlas Tube

Schedule B

Transactions in Securities of the Issuer During the Past Sixty Days

Exhibit 1

JOINT FILING AGREEMENT

July 31, 2024

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D filed on the date hereof (including amendments thereto) with respect to the Common Shares, without par value, of Algoma Steel Group, Inc. This Joint Filing Agreement shall be filed as an Exhibit to such Statement.