William Blair Investment Management’s Avantor AVTR Stock Holding History

William Blair Investment Management’s Portfolio AVTR Stock Details AVTR Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2025 Q3	–	Sell	-22,225	Closed	-$299K	–	417
2025 Q2	$299K	Sell	22,225 -4,410,817	-99%	-$60.4M	﹤0.01%	399
2025 Q1	$71.9M	Sell	4,433,042 -315,873	-7%	-$5.98M	0.2%	122
2024 Q4	$100M	Sell	4,748,915 -116,501	-2%	-$2.62M	0.24%	116
2024 Q3	$126M	Buy	4,865,416 +3,811,333	+362%	+$93.6M	0.31%	105
2024 Q2	$22.3M	Buy	1,054,083 +6,351	+0.6%	+$153K	0.06%	287
2024 Q1	$26.8M	Buy	1,047,732 +322,985	+45%	+$7.68M	0.07%	270
2023 Q4	$16.5M	Sell	724,747 -75,734	-9%	-$1.55M	0.05%	306
2023 Q3	$16.9M	Buy	800,481 +78,615	+11%	+$1.67M	0.06%	292
2023 Q2	$14.8M	Buy	721,866 +106,653	+17%	+$2.16M	0.05%	304
2023 Q1	$13M	Buy	+615,213	New	+$14M	0.05%	305

Other funds holding AVTR

Dodge & Cox San Francisco, California $191B AUM 17.5% 1-Year Est. Return

Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Barrow, Hanley, Mewhinney & Strauss Dallas, Texas $33B AUM 40.62% 1-Year Est. Return

T. Rowe Price Investment Management Baltimore, Maryland $153B AUM 38.14% 1-Year Est. Return

State Street Boston, Massachusetts $3.38T AUM 44.17% 1-Year Est. Return

ECM

Engine Capital Management New York $1.03B AUM 4.33% 1-Year Est. Return

Greenhaven Associates Purchase, New York $8.66B AUM 17.37% 1-Year Est. Return

Invesco Atlanta, Georgia $1.26T AUM 61.52% 1-Year Est. Return

CCP

Clarkston Capital Partners Rochester, Michigan $1.18B AUM 0.37% 1-Year Est. Return

William Blair Investment Management's AVTR Position: Q3 2025 in Review

William Blair Investment Management sold out of Avantor (AVTR) in Q3 2025, closing a stake of 22,225 shares — an estimated $299K sold.

William Blair Investment Management first reported a position in AVTR in Q1 2023 and held it in 10 quarters. The position peaked at $126M in Q3 2024. 466 funds tracked by Wall St. Rank hold AVTR as of Q3 2025.

William Blair Investment Management reported no remaining Avantor position as of Q3 2025 after selling out during the quarter.
William Blair Investment Management sold 22,225 Avantor shares in Q3 2025, an estimated $299K.
William Blair Investment Management first reported a position in Avantor in Q1 2023 and held it in 10 quarters.
William Blair Investment Management's Avantor position peaked at $126M in Q3 2024.
466 funds tracked by Wall St. Rank held Avantor as of Q3 2025.

Based on William Blair Investment Management's 13F filing for Q3 2025, filed 12 Nov 2025.