William Blair Investment Management
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William Blair Investment Management’s Halozyme HALO Stock Holding History

William Blair Investment Management’s Portfolio HALO Stock Details HALO Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$163M Buy
2,525,975
+683,019
+37% +$48.1M 0.54% 46
2025
Q4 		$124M Buy
+1,842,956
New +$124M 0.35% 78
2023
Q1 		– Sell
-3,706,003
Closed -$211M – 406
2022
Q4 		$211M Sell
3,706,003
-730,081
-16% -$37.4M 0.81% 31
2022
Q3 		$175M Sell
4,436,084
-130,787
-3% -$5.78M 0.69% 45
2022
Q2 		$201M Sell
4,566,871
-773,020
-14% -$33.4M 0.74% 34
2022
Q1 		$213M Buy
5,339,891
+266,226
+5% +$9.48M 0.64% 46
2021
Q4 		$204M Buy
5,073,665
+76,957
+2% +$2.87M 0.55% 60
2021
Q3 		$203M Buy
4,996,708
+114,222
+2% +$4.78M 0.57% 55
2021
Q2 		$222M Sell
4,882,486
-454,976
-9% -$20.1M 0.7% 46
2021
Q1 		$223M Sell
5,337,462
-1,024,882
-16% -$46.8M 0.72% 46
2020
Q4 		$272M Sell
6,362,344
-158,182
-2% -$5.69M 0.9% 26
2020
Q3 		$171M Sell
6,520,526
-58,086
-0.9% -$1.62M 0.67% 58
2020
Q2 		$176M Buy
6,578,612
+15,006
+0.2% +$339K 0.72% 48
2020
Q1 		$118M Buy
6,563,606
+232,076
+4% +$4.4M 0.57% 55
2019
Q4 		$112M Buy
6,331,530
+915,535
+17% +$15.9M 0.45% 72
2019
Q3 		$84M Buy
5,415,995
+1,877,068
+53% +$30.9M 0.36% 87
2019
Q2 		$60.8M Buy
3,538,927
+3,134,003
+774% +$50.6M 0.26% 108
2019
Q1 		$6.52M Buy
+404,924
New +$6.56M 0.03% 334

Other funds holding HALO

BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
Invesco
Invesco Atlanta, Georgia $1.02T AUM 30.18% 1-Year Est. Return
Bank of America
Bank of America Charlotte, North Carolina $1.37T AUM 24.88% 1-Year Est. Return
Boston Partners
Boston Partners Boston, Massachusetts $113B AUM 38.87% 1-Year Est. Return
Morgan Stanley
Morgan Stanley New York $1.66T AUM 25.57% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
SCM
Snyder Capital Management San Francisco, California $5.16B AUM 26.72% 1-Year Est. Return

William Blair Investment Management's HALO Position: Q1 2026 in Review

William Blair Investment Management increased its Halozyme (HALO) stake by 37% in Q1 2026, buying an estimated $48.1M and bringing the position to 2,525,975 shares worth $163M. The position accounts for 0.54% of the portfolio, ranked #46.

William Blair Investment Management first reported a position in HALO in Q1 2019 and has held it in 18 quarters since. The position peaked at $272M in Q4 2020. 635 funds tracked by Wall St. Rank hold HALO as of Q1 2026.

  • William Blair Investment Management held 2,525,975 shares of Halozyme worth $163M as of Q1 2026.
  • William Blair Investment Management bought 683,019 Halozyme shares in Q1 2026, an estimated $48.1M.
  • Halozyme made up 0.54% of William Blair Investment Management's portfolio in Q1 2026, its #46 holding.
  • William Blair Investment Management first reported a position in Halozyme in Q1 2019 and has held it in 18 quarters since.
  • William Blair Investment Management's Halozyme position peaked at $272M in Q4 2020.
  • 635 funds tracked by Wall St. Rank held Halozyme as of Q1 2026.

Based on William Blair Investment Management's 13F filing for Q1 2026, filed 8 May 2026.