Mason Capital Management’s ATS Corp ATS Stock Holding History

Mason Capital Management’s Portfolio ATS Stock Details ATS Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2026 Q2	$472M	Hold	16,404,170	–	–	77.78%	1
2026 Q1	$463M	Buy	16,404,170 +840,602	+5%	+$25.3M	75.48%	1
2025 Q4	$429M	Hold	15,563,568	–	–	76.32%	1
2025 Q3	$408M	Hold	15,563,568	–	–	82.99%	1
2025 Q2	$496M	Hold	15,563,568	–	–	97%	1
2025 Q1	$388M	Buy	15,563,568 +648,803	+4%	+$18.1M	90.83%	1
2024 Q4	$455M	Hold	14,914,765	–	–	96.62%	1
2024 Q3	$433M	Buy	14,914,765 +565,000	+4%	+$16.3M	86.21%	1
2024 Q2	$464M	Hold	14,349,765	–	–	86.14%	1
2024 Q1	$654M	Sell	14,349,765 -3,500,000	-20%	-$139M	89.87%	1
2023 Q4	$769M	Hold	17,849,765	–	–	86.01%	1
2023 Q3	$761M	Hold	17,849,765	–	–	65.44%	1
2023 Q2	$823M	Buy	+17,849,765	New	+$802M	80.16%	1

Other funds holding ATS

Royal Bank of Canada Toronto, Ontario, Canada $672B AUM 33.48% 1-Year Est. Return

EIG

EdgePoint Investment Group Toronto, Ontario, Canada $13.2B AUM 32.43% 1-Year Est. Return

BGC

Beutel, Goodman & Co Toronto, Ontario, Canada $13.6B AUM 17.82% 1-Year Est. Return

TCAM

Turtle Creek Asset Management Toronto, Ontario, Canada $2.56B AUM 1.05% 1-Year Est. Return

Bank of Montreal Toronto, Ontario, Canada $304B AUM 35.64% 1-Year Est. Return

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

FFH

Fairfax Financial Holdings Toronto, Ontario, Canada $2.64B AUM 24.46% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

Jupiter Topco New York $245B AUM

HCC

Hill City Capital Boston, Massachusetts $4.28B AUM 80.76% 1-Year Est. Return

Mason Capital Management's ATS Position: Q2 2026 in Review

Mason Capital Management held its ATS Corp (ATS) position steady in Q2 2026 at 16,404,170 shares worth $472M. The position accounts for 77.78% of the portfolio, ranked #1.

Mason Capital Management first reported a position in ATS in Q2 2023 and has held it in 13 quarters since. The position peaked at $823M in Q2 2023. 141 funds tracked by Wall St. Rank hold ATS as of Q2 2026.

Mason Capital Management held 16,404,170 shares of ATS Corp worth $472M as of Q2 2026.
Mason Capital Management left its ATS Corp share count unchanged in Q2 2026.
ATS Corp made up 77.78% of Mason Capital Management's portfolio in Q2 2026, its #1 holding.
Mason Capital Management first reported a position in ATS Corp in Q2 2023 and has held it in 13 quarters since.
Mason Capital Management's ATS Corp position peaked at $823M in Q2 2023.
141 funds tracked by Wall St. Rank held ATS Corp as of Q2 2026.

Based on Mason Capital Management's 13F filing for Q2 2026, filed 14 Aug 2026.