Stock Ownership/ATI

ATI INC (ATI): Ownership & Insider Activity

Hedge funds and institutional managers reporting a position in ATI · Materials. Based on the most recent 13F filing from each holder, sourced from SEC EDGAR.

Reported Holders
36
13F filers
Aggregate Value
$2.9B
Across holders
Last Price
$209.81
2026-08-24
Sector
Materials
GICS
Quarterly fund activity20 increased16 reduced2 exited
Full exits: Woodline Partners LP, ADAGE CAPITAL PARTNERS GP, L.L.C.
Institutional Holders of ATI
↗
36 holders
Manager⇅Type⇅Shares⇅Market Value▼% of Total⇅% of Portfolio⇅Action⇅QoQ Change⇅Quarter⇅
Qube Research & Technologies Ltd
CIK 0001729829
Hedge Fund2.14M$422.6M14.8%0.4%Added+$253.3MQ2 2026
AQR CAPITAL MANAGEMENT LLC
CIK 0001167557
Hedge Fund1.43M$282.4M9.9%0.1%Added+$280.7MQ2 2026
Point72 Asset Management, L.P.
CIK 0001603466
Hedge Fund1.24M$244.5M8.6%0.3%Reduced+$243.1MQ2 2026
VIKING GLOBAL INVESTORS LP
CIK 0001103804
Hedge Fund1.15M$227.4M8.0%0.6%Reduced$-429.5MQ2 2026
MILLENNIUM MANAGEMENT LLC
CIK 0001273087
Hedge Fund875K$172.5M6.0%0.1%Added+$172.0MQ2 2026
Fisher Asset Management, LLC
CIK 0000850529
Institutional Manager872K$171.9M6.0%0.1%Reduced$-10.3MQ2 2026
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP
CIK 0001164508
Hedge Fund840K$165.5M5.8%0.1%Reduced$-71.7MQ2 2026
SHAW D E & CO INC
CIK 0001009207
Hedge Fund816K$160.8M5.6%0.1%Reduced$-398.5MQ2 2026
MARSHALL WACE, LLP
CIK 0001318757
Hedge Fund710K$139.9M4.9%0.1%Added+$57.8MQ2 2026
TWO SIGMA INVESTMENTS, LP
CIK 0001179392
Hedge Fund637K$125.5M4.4%0.1%Added+$124.8MQ2 2026
Qube Research & Technologies LtdAdded
Hedge Fund
$422.6M· 14.8% of total· 0.4% port· 2.14M sh· +$253.3M QoQ· Q2 2026
AQR CAPITAL MANAGEMENT LLCAdded
Hedge Fund
$282.4M· 9.9% of total· 0.1% port· 1.43M sh· +$280.7M QoQ· Q2 2026
Point72 Asset Management, L.P.Reduced
Hedge Fund
$244.5M· 8.6% of total· 0.3% port· 1.24M sh· +$243.1M QoQ· Q2 2026
VIKING GLOBAL INVESTORS LPReduced
Hedge Fund
$227.4M· 8.0% of total· 0.6% port· 1.15M sh· $-429.5M QoQ· Q2 2026
MILLENNIUM MANAGEMENT LLCAdded
Hedge Fund
$172.5M· 6.0% of total· 0.1% port· 875K sh· +$172.0M QoQ· Q2 2026
Fisher Asset Management, LLCReduced
Institutional Manager
$171.9M· 6.0% of total· 0.1% port· 872K sh· $-10.3M QoQ· Q2 2026
ARROWSTREET CAPITAL, LIMITED PARTNERSHIPReduced
Hedge Fund
$165.5M· 5.8% of total· 0.1% port· 840K sh· $-71.7M QoQ· Q2 2026
SHAW D E & CO INCReduced
Hedge Fund
$160.8M· 5.6% of total· 0.1% port· 816K sh· $-398.5M QoQ· Q2 2026
MARSHALL WACE, LLPAdded
Hedge Fund
$139.9M· 4.9% of total· 0.1% port· 710K sh· +$57.8M QoQ· Q2 2026
TWO SIGMA INVESTMENTS, LPAdded
Hedge Fund
$125.5M· 4.4% of total· 0.1% port· 637K sh· +$124.8M QoQ· Q2 2026
BALYASNY ASSET MANAGEMENT LLCReduced
Hedge Fund
$101.3M· 3.5% of total· 0.1% port· 514K sh· $-234.4M QoQ· Q2 2026
Holocene Advisors, LPReduced
Hedge Fund
$98.1M· 3.4% of total· 0.2% port· 498K sh· $-118.3M QoQ· Q2 2026
CITADEL ADVISORS LLCAdded
Hedge Fund
$98.0M· 3.4% of total· 0.0% port· 497K sh· +$16.6M QoQ· Q2 2026
GAMCO INVESTORS, INC. ET ALReduced
Institutional Manager
$70.6M· 2.5% of total· 0.6% port· 358K sh· $-690K QoQ· Q2 2026
Clearbridge Investments, LLCAdded
Hedge Fund
$55.3M· 1.9% of total· 0.0% port· 280K sh· — QoQ· Q2 2026
Gotham Asset Management, LLCAdded
Hedge Fund
$53.1M· 1.9% of total· 0.1% port· 270K sh· +$1.8M QoQ· Q2 2026
JUPITER ASSET MANAGEMENT LTDReduced
Hedge Fund
$39.9M· 1.4% of total· 0.2% port· 203K sh· $-66.5M QoQ· Q2 2026
Rokos Capital Management LLPAdded
Hedge Fund
$35.7M· 1.2% of total· 0.1% port· 181K sh· +$19.8M QoQ· Q2 2026
Schonfeld Strategic Advisors LLCAdded
Hedge Fund
$35.0M· 1.2% of total· 0.1% port· 178K sh· +$30.4M QoQ· Q2 2026
TUDOR INVESTMENT CORP ET ALAdded
Hedge Fund
$29.3M· 1.0% of total· 0.0% port· 149K sh· +$25.7M QoQ· Q2 2026
Brevan Howard Capital Management LPAdded
Hedge Fund
$23.2M· 0.8% of total· 0.2% port· 118K sh· +$16.4M QoQ· Q2 2026
Bridgewater Associates, LPAdded
Hedge Fund
$22.7M· 0.8% of total· 0.1% port· 115K sh· +$18.3M QoQ· Q2 2026
Walleye Capital LLCReduced
Hedge Fund
$15.3M· 0.5% of total· 0.1% port· 77K sh· +$10.7M QoQ· Q2 2026
SOROS FUND MANAGEMENT LLCAdded
Family Office
$14.5M· 0.5% of total· 0.2% port· 73K sh· +$4.0M QoQ· Q2 2026
ExodusPoint Capital Management, LPAdded
Hedge Fund
$14.4M· 0.5% of total· 0.1% port· 73K sh· — QoQ· Q2 2026
Man Group plcAdded
Hedge Fund
$11.7M· 0.4% of total· 0.0% port· 60K sh· +$10.9M QoQ· Q2 2026
Hudson Bay Capital Management LPAdded
Hedge Fund
$10.0M· 0.4% of total· 0.0% port· 51K sh· +$9.9M QoQ· Q2 2026
MOORE CAPITAL MANAGEMENT, LPReduced
Hedge Fund
$6.1M· 0.2% of total· 0.1% port· 31K sh· $-589K QoQ· Q2 2026
CAPSTONE INVESTMENT ADVISORS, LLCReduced
Hedge Fund
$2.1M· 0.1% of total· 0.0% port· 11K sh· $-2.8M QoQ· Q2 2026
Squarepoint Ops LLCReduced
Hedge Fund
$1.8M· 0.1% of total· 0.0% port· 9K sh· $-4.4M QoQ· Q2 2026
Magnetar Financial LLCAdded
Hedge Fund
$1.2M· 0.0% of total· 0.0% port· 6K sh· — QoQ· Q2 2026
Rockefeller Capital Management L.P.Reduced
Hedge Fund
$998K· 0.0% of total· 0.0% port· 5K sh· $-2.8M QoQ· Q2 2026
Verition Fund Management LLCReduced
Hedge Fund
$508K· 0.0% of total· 0.0% port· 3K sh· $-7.2M QoQ· Q2 2026
TCW GROUP INCAdded
Hedge Fund
$445K· 0.0% of total· 0.0% port· 2K sh· +$8K QoQ· Q2 2026
CAXTON ASSOCIATES LLPAdded
Hedge Fund
$249K· 0.0% of total· 0.0% port· 1K sh· — QoQ· Q2 2026
Alphadyne Asset Management LPReduced
Hedge Fund
$23K· 0.0% of total· 0.0% port· 117 sh· $-2.6M QoQ· Q2 2026
1–10 of 36
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