William Blair Investment Management
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William Blair Investment Management’s Atmus Filtration Technologies ATMU Stock Holding History

William Blair Investment Management’s Portfolio ATMU Stock Details ATMU Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		$20.7M Sell
405,168
-20,904
-5% -$1.14M 0.06% 245
2026
Q1 		$24.2M Sell
426,072
-255,900
-38% -$15.1M 0.08% 232
2025
Q4 		$35.4M Sell
681,972
-69,785
-9% -$3.38M 0.1% 176
2025
Q3 		$33.9M Sell
751,757
-45,526
-6% -$1.91M 0.09% 189
2025
Q2 		$29M Sell
797,283
-62,808
-7% -$2.24M 0.08% 222
2025
Q1 		$31.6M Buy
+860,091
New +$33.9M 0.09% 209

Other funds holding ATMU

BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Fidelity Investments
Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
Invesco
Invesco Atlanta, Georgia $1.26T AUM 61.52% 1-Year Est. Return
T. Rowe Price Associates
T. Rowe Price Associates Baltimore, Maryland $999B AUM 46.22% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
State Street
State Street Boston, Massachusetts $3.38T AUM 44.17% 1-Year Est. Return
Goldman Sachs
Goldman Sachs New York $1.15T AUM 47.82% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
Neuberger Berman Group
Neuberger Berman Group New York $150B AUM 40.08% 1-Year Est. Return

William Blair Investment Management's ATMU Position: Q2 2026 in Review

William Blair Investment Management reduced its Atmus Filtration Technologies (ATMU) stake by 4.9% in Q2 2026, selling an estimated $1.14M and leaving 405,168 shares worth $20.7M. The position accounts for 0.06% of the portfolio, ranked #245.

William Blair Investment Management first reported a position in ATMU in Q1 2025 and has held it in 6 quarters since. The position peaked at $35.4M in Q4 2025. 335 funds tracked by Wall St. Rank hold ATMU as of Q2 2026.

  • William Blair Investment Management held 405,168 shares of Atmus Filtration Technologies worth $20.7M as of Q2 2026.
  • William Blair Investment Management sold 20,904 Atmus Filtration Technologies shares in Q2 2026, an estimated $1.14M.
  • Atmus Filtration Technologies made up 0.06% of William Blair Investment Management's portfolio in Q2 2026, its #245 holding.
  • William Blair Investment Management first reported a position in Atmus Filtration Technologies in Q1 2025 and has held it in 6 quarters since.
  • William Blair Investment Management's Atmus Filtration Technologies position peaked at $35.4M in Q4 2025.
  • 335 funds tracked by Wall St. Rank held Atmus Filtration Technologies as of Q2 2026.

Based on William Blair Investment Management's 13F filing for Q2 2026, filed 12 Aug 2026.