Turtle Creek Asset Management filed Amendment No. 3 to a Schedule 13G/A reporting beneficial ownership of 4,896,669 common shares of ATS Corp, representing 4.99% of the class. The filing states Turtle Creek holds these shares as investment advisor for mutual fund unit holders. The amendment is signed by Meaghan Einav, Chief Compliance Officer, dated 05/15/2026.
Positive
None.
Negative
None.
Insights
Amendment reports below-5% passive holdings held for funds.
The amendment updates beneficial ownership to 4,896,669 shares (4.99%) and identifies Turtle Creek as an investment advisor holding the position for mutual fund unit holders. The filing emphasizes regulatory comparability with Ontario authorities and an undertaking to provide Schedule 13D-level information if requested.
Because the position is reported as passive and under the 5% threshold, the disclosure is administrative; subsequent filings would be needed if ownership crosses thresholds or voting/dispositive powers change.
Position size and stewardship are clear; sale or accumulation intent not disclosed.
The statement lists sole voting and dispositive power of 4,896,669 shares and notes ownership is on behalf of mutual fund holders. It does not state plans to buy or sell or identify any controlling intent, consistent with a Schedule 13G passive disclosure.
Future material change in percent ownership or a Schedule 13D filing would be the primary event to watch for changes in stewardship or potential activist intent.
Key Figures
Beneficial ownership:4,896,669 sharesPercent of class:4.99%CUSIP:00217Y104+1 more
4 metrics
Beneficial ownership4,896,669 sharesReported on Schedule 13G/A Amendment No. 3
Percent of class4.99%Percent of ATS common shares reported
CUSIP00217Y104ATS Corp Common Shares identifier
Filing signature date05/15/2026Signature by Chief Compliance Officer Meaghan Einav
Key Terms
Schedule 13G/A, beneficially owned, sole dispositive power
3 terms
Schedule 13G/Aregulatory
"This statement on is being filed by Turtle Creek Asset Management Inc."
A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.
beneficially ownedregulatory
"Amount beneficially owned: See the response(s) to Item 9 on the attached cover page."
Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.
sole dispositive powerregulatory
"Sole Dispositive Power 4,896,669.00"
Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 3)
ATS Corp /ATS
(Name of Issuer)
Common Shares
(Title of Class of Securities)
00217Y104
(CUSIP Number)
03/31/2026
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
00217Y104
1
Names of Reporting Persons
Turtle Creek Asset Management Inc.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
CANADA (FEDERAL LEVEL)
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
4,896,669.00
6
Shared Voting Power
0.00
7
Sole Dispositive Power
4,896,669.00
8
Shared Dispositive Power
0.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
4,896,669.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
4.99 %
12
Type of Reporting Person (See Instructions)
FI
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
ATS Corp /ATS
(b)
Address of issuer's principal executive offices:
730 Fountain Street North, Building 3, Cambridge, Ontario, Canada, N3H 4R7
Item 2.
(a)
Name of person filing:
This statement on Schedule 13G is being filed by Turtle Creek Asset Management Inc. ("Turtle Creek").
(b)
Address or principal business office or, if none, residence:
Scotia Plaza, 40 King Street West, Suite 5100, Toronto, Ontario M5H 3Y2 Canada
(c)
Citizenship:
Canada
(d)
Title of class of securities:
Common Shares
(e)
CUSIP No.:
00217Y104
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Investment advisor
Item 4.
Ownership
(a)
Amount beneficially owned:
See the response(s) to Item 9 on the attached cover page.
(b)
Percent of class:
See the response(s) to Item 11 on the attached cover page.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
See the response(s) to Item 5 on the attached cover page.
(ii) Shared power to vote or to direct the vote:
See the response(s) to Item 6 on the attached cover page.
(iii) Sole power to dispose or to direct the disposition of:
See the response(s) to Item 7 on the attached cover page.
(iv) Shared power to dispose or to direct the disposition of:
See the response(s) to Item 8 on the attached cover page.
Item 5.
Ownership of 5 Percent or Less of a Class.
Ownership of 5 percent or less of a class
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
Turtle Creek holds the Common Shares reported herein for the benefit of unit holders of mutual funds managed by Turtle Creek, none of whom is known to Turtle Creek to have an interest of more than 5 percent of the class.
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.
By signing below I certify that, to the best of my knowledge and belief, the foreign regulatory scheme applicable to investment fund managers and portfolio managers registered with the Ontario Securities Commission is substantially comparable to the regulatory scheme applicable to the functionally equivalent U.S. institution(s). I also undertake to furnish to the Commission staff, upon request, information that would otherwise be disclosed in a Schedule 13D.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
Who filed the Schedule 13G/A for ATS (ATS) and what stake is reported?
Turtle Creek Asset Management filed the amendment reporting 4,896,669 shares, representing 4.99% of ATS Corp common stock as disclosed in the filing.
Does Turtle Creek report voting or dispositive power over ATS shares?
Yes. The filing shows Turtle Creek has sole voting power and sole dispositive power over 4,896,669 shares of ATS Corp according to Item 5–8 on the cover data.
Are the ATS shares held directly by Turtle Creek or for others?
The filing states Turtle Creek holds the reported Common Shares for the benefit of mutual fund unit holders, and it does not identify any underlying holder with more than 5% of the class.
Does this Schedule 13G/A indicate activist intent or control filing?
No. The amendment characterizes the holding as a passive investment by an investment advisor for funds; it does not assert control or activist intent and remains under the 5% threshold.
When was the amendment signed and who signed it?
The document is signed by Meaghan Einav, Chief Compliance Officer, with the signature date of 05/15/2026, as shown on the filing.
