William Blair & Company
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William Blair & Company’s Alnylam Pharmaceuticals ALNY Stock Holding History

William Blair & Company’s Portfolio ALNY Stock Details ALNY Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		$3.57M Buy
11,853
+2,423
+26% +$731K 0.01% 608
2026
Q1 		$3.12M Sell
9,430
-344
-4% -$117K 0.01% 618
2025
Q4 		$3.89M Sell
9,774
-470
-5% -$208K 0.01% 584
2025
Q3 		$4.67M Sell
10,244
-348
-3% -$142K 0.01% 533
2025
Q2 		$3.45M Sell
10,592
-486
-4% -$134K 0.01% 589
2025
Q1 		$2.99M Sell
11,078
-884
-7% -$227K 0.01% 615
2024
Q4 		$2.81M Sell
11,962
-1,372
-10% -$361K 0.01% 642
2024
Q3 		$3.67M Buy
+13,334
New +$3.47M 0.01% 570

Other funds holding ALNY

Fidelity Investments
Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return
Capital World Investors
Capital World Investors Los Angeles, California $846B AUM 46.74% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Capital Research Global Investors
Capital Research Global Investors Los Angeles, California $717B AUM 35.42% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
T. Rowe Price Investment Management
T. Rowe Price Investment Management Baltimore, Maryland $153B AUM 38.14% 1-Year Est. Return
Invesco
Invesco Atlanta, Georgia $1.26T AUM 61.52% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return

William Blair & Company's ALNY Position: Q2 2026 in Review

William Blair & Company increased its Alnylam Pharmaceuticals (ALNY) stake by 26% in Q2 2026, buying an estimated $731K and bringing the position to 11,853 shares worth $3.57M. The position accounts for 0.01% of the portfolio, ranked #608.

William Blair & Company first reported a position in ALNY in Q3 2024 and has held it in 8 quarters since. The position peaked at $4.67M in Q3 2025. 791 funds tracked by Wall St. Rank hold ALNY as of Q2 2026.

  • William Blair & Company held 11,853 shares of Alnylam Pharmaceuticals worth $3.57M as of Q2 2026.
  • William Blair & Company bought 2,423 Alnylam Pharmaceuticals shares in Q2 2026, an estimated $731K.
  • Alnylam Pharmaceuticals made up 0.01% of William Blair & Company's portfolio in Q2 2026, its #608 holding.
  • William Blair & Company first reported a position in Alnylam Pharmaceuticals in Q3 2024 and has held it in 8 quarters since.
  • William Blair & Company's Alnylam Pharmaceuticals position peaked at $4.67M in Q3 2025.
  • 791 funds tracked by Wall St. Rank held Alnylam Pharmaceuticals as of Q2 2026.

Based on William Blair & Company's 13F filing for Q2 2026, filed 11 Aug 2026.