13F filer

William Blair Investment Management

As of Jun 30, 2026 Filed Aug 12, 2026 CIK 1644956 SEC filings ↗

13F Value

$33.25B

Positions

403

Top Position

TSM7.1%

Top 5

20.9%

Latest filing changes

vs Mar 31, 2026

1 GOOGL Alphabet Class A +27.4%+$245.3M

2 TEVA Teva Pharmaceutical Inds +362.5%+$175.1M

3 TKR Timken >999%+$138.0M

4 WST West Pharmaceutical Svsc +950.5%+$135.6M

5 MIRM Mirum Pharmaceuticals +318.5%+$125.2M

Holdings403

#							Trend (4Q)
1	TSM Taiwan Semiconductor Manufacturing	7.1%	$2.36B	-10.5%	4.94M	6.2%		ADR
2	NVDA NVIDIA	5.2%	$1.72B	-3.8%	8.60M	5.2%		Common Stock
3	GOOGL Alphabet Class A Filing details 02079K305 Jun 30, 2026 3,191,012 reported quantity $1,140,372,074 reported value	3.4%	$1.14B	+27.4%	3.19M	2.4%		Common Stock
4	AAPL Apple	2.8%	$943.3M	-32.3%	3.26M	4.0%		Common Stock
5	AVGO Broadcom	2.3%	$776.7M	-6.6%	2.06M	2.3%		Common Stock
6	MSFT Microsoft	2.3%	$764.2M	-29.3%	2.05M	3.5%		Common Stock
7	META Meta Platforms	1.6%	$535.2M	-6.2%	950.1K	1.9%		Common Stock
8	AMZN Amazon	1.4%	$473.6M	-37.2%	1.99M	2.2%		Common Stock
9	MA Mastercard	1.4%	$471.5M	-13.4%	918.0K	1.8%		Common Stock
10	AMD Advanced Micro Devices	1.3%	$443.5M	-26.8%	763.5K	0.7%		Common Stock
11	AMAT Applied Materials	1.1%	$360.0M	—	497.9K	<0.1%	—	Common Stock
12	GE Ge Aerospace Filing details 369604301 Jun 30, 2026 790,801 reported quantity $295,546,058 reported value	0.9%	$295.5M	NEW	790.8K	—		Common Stock
13	AZN AstraZeneca Filing details G0593M107 Jun 30, 2026 1,514,795 reported quantity $283,249,808 reported value	0.9%	$283.2M	-22.0%	1.51M	1.2%		Common Stock
14	PRMB Primo Brands	0.8%	$279.3M	-12.5%	11.43M	0.8%		Common Stock
15	P Everpure	0.8%	$272.2M	+19.9%	3.46M	0.6%		Common Stock
16	APH Amphenol	0.8%	$270.7M	+42.5%	1.54M	0.4%		Common Stock
17	LIN Linde Filing details G54950103 Jun 30, 2026 504,953 reported quantity $262,040,310 reported value	0.8%	$262.0M	-20.6%	505.0K	1.0%		Common Stock
18	ONTO Onto Innovation	0.8%	$251.8M	-31.0%	665.4K	0.7%		Common Stock
19	BWA Borgwarner	0.8%	$251.3M	+31.2%	3.78M	0.5%		Common Stock
20	CG Carlyle Group	0.7%	$249.1M	-6.1%	5.91M	1.0%		Common Stock

Change compares with the prior filing. Prior % is the share of the portfolio in that filing. Trend shows the quantity held in each of the last four filings: green rose, red fell, grey unchanged.

Exited in Latest Filing56

#	Holding	Prior %	Prior Value	Change	Prior Quantity	Trend (4Q)	Type

Compared with the immediately prior published filing (Mar 31, 2026). Prior values are shown for context and are not included in current totals.