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William Blair Investment Management Portfolio holdings
AUM
$30.3B
1-Year Est. Return
33.75%
This Fund
S&P 500
This Quarter
Est. Return
-0.1%
1 Year Est. Return
+33.75%
3 Year Est. Return
+108.55%
5 Year Est. Return
+126.9%
10 Year Est. Return
+771.69%
AUM
$30.3B
AUM Growth
-$5.59B
(-16%)
Cap. Flow
-$4.09B
Cap. Flow
% of AUM
-13.52%
Top 10 Holdings %
Top 10 Hldgs %
30.62%
Holding
459
New
46
Increased
157
Reduced
205
Closed
46
Top Buys
| Rank | Stock | Value |
|---|---|---|
| 1 |
AstraZeneca
AZN
|
+$370M |
| 2 |
Akamai
AKAM
|
+$162M |
| 3 |
BorgWarner
BWA
|
+$152M |
| 4 |
Amphenol
APH
|
+$152M |
| 5 |
Synaptics
SYNA
|
+$129M |
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
NVIDIA
NVDA
|
+$309M |
| 2 |
Sea Limited
SE
|
+$302M |
| 3 |
Amazon
AMZN
|
+$269M |
| 4 |
Microsoft
MSFT
|
+$248M |
| 5 |
Ciena
CIEN
|
+$214M |
Sector Composition
| Rank | Sector | Weight |
|---|---|---|
| 1 | Technology | 36.13% |
| 2 | Healthcare | 12.59% |
| 3 | Industrials | 11.81% |
| 4 | Financials | 11.55% |
| 5 | Consumer Discretionary | 10.11% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
1
TSMC
TSM
$2.09T
| $1.87B | 6.16% |
5,518,260
-467,070
| -8% | -$161M |
|
|
2
NVIDIA
NVDA
$5.01T
| $1.56B | 5.15% |
8,941,756
-1,686,911
| -16% | -$309M |
|
3
Apple
AAPL
$4.89T
| $1.22B | 4.04% |
4,812,433
-631,895
| -12% | -$164M |
|
|
4
Microsoft
MSFT
$2.84T
| $1.07B | 3.54% |
2,896,782
-593,520
| -17% | -$248M |
|
5
Alphabet (Google) Class A
GOOGL
$3.91T
| $720M | 2.38% |
2,504,605
-650,368
| -21% | -$204M |
|
6
Broadcom
AVGO
$1.82T
| $681M | 2.25% |
2,201,558
-335,053
| -13% | -$110M |
|
|
7
Amazon
AMZN
$2.5T
| $659M | 2.18% |
3,163,629
-1,223,374
| -28% | -$269M |
|
8
Meta Platforms (Facebook)
META
$1.51T
| $580M | 1.92% |
1,013,122
-173,647
| -15% | -$111M |
|
9
Mastercard
MA
$477B
| $530M | 1.75% |
1,060,651
-24,296
| -2% | -$12.8M |
|
|
10
AstraZeneca
AZN
$263B
| $377M | 1.25% |
1,942,155
+1,918,625
| +8,154% | +$370M |
|
11
Linde
LIN
$237B
| $315M | 1.04% |
636,338
-7,132
| -1% | -$3.36M |
|
12
Carlyle Group
CG
$16.3B
| $305M | 1.01% |
6,301,109
-830,793
| -12% | -$45.8M |
|
13
Costco
COST
$415B
| $301M | 1% |
302,468
-26,000
| -8% | -$25.3M |
|
14
Itaú Unibanco
ITUB
$91.3B
| $266M | 0.88% |
31,684,708
-4,867,055
| -13% | -$40.7M |
|
15
Twist Bioscience
TWST
$5.62B
| $250M | 0.83% |
5,269,718
-684,711
| -11% | -$30.7M |
|
16
ServiceNow
NOW
$102B
| $248M | 0.82% |
2,371,614
+222,834
| +10% | +$26.2M |
|
|
PRMB
17
Primo Brands
PRMB
$8.24B
| $246M | 0.81% |
13,056,192
+428,772
| +3% | +$8.28M |
|
18
Mueller Industries
MLI
$14.1B
| $234M | 0.77% |
4,219,458
+659,646
| +19% | +$39.6M |
|
19
Intuit
INTU
$81.1B
| $231M | 0.76% |
533,736
+91,345
| +21% | +$43.6M |
|
20
Monster Beverage
MNST
$91.4B
| $213M | 0.7% |
2,935,247
-826,002
| -22% | -$65.1M |
|
21
Advanced Micro Devices
AMD
$851B
| $212M | 0.7% |
1,042,594
-296,952
| -22% | -$63.4M |
|
22
Credicorp
BAP
$30.9B
| $211M | 0.7% |
622,690
-144,723
| -19% | -$48.5M |
|
23
Agilent Technologies
A
$39.1B
| $205M | 0.68% |
1,795,764
-267,245
| -13% | -$33.9M |
|
24
O'Reilly Automotive
ORLY
$72.4B
| $204M | 0.67% |
2,210,034
-771,473
| -26% | -$72.4M |
|
25
BWX Technologies
BWXT
$16B
| $201M | 0.66% |
981,782
-125,818
| -11% | -$25.6M |
|
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William Blair Investment Management's Q1 2026 Portfolio in Review
As of Q1 2026, William Blair Investment Management held 459 positions worth $30.3B, down 16% from $35.9B the previous quarter. Its ten largest holdings account for 31% of the portfolio.
William Blair Investment Management withdrew a net $4.09B in Q1 2026, closing 46 positions and reducing 205 holdings. Its most notable exit was Sea Limited, an estimated $302M position sold in full.
By sector, the portfolio is most concentrated in Technology at 36% of assets, down from 38% a quarter earlier, followed by Healthcare and Industrials.
Against the trend, William Blair Investment Management opened a new position in Akamai worth $186M.
- William Blair Investment Management's largest Q1 2026 buy was Akamai: 1,619,060 shares worth $186M.
- William Blair Investment Management added most to AstraZeneca in Q1 2026, an estimated $370M increase.
- William Blair Investment Management's biggest Q1 2026 reduction was NVIDIA, cutting an estimated $309M.
- William Blair Investment Management fully exited Sea Limited in Q1 2026, selling an estimated $302M.
- William Blair Investment Management's ten largest holdings make up 31% of its $30.3B portfolio in Q1 2026.
- William Blair Investment Management opened 46 new positions and closed 46 in Q1 2026.
- William Blair Investment Management's portfolio value fell 16% quarter-over-quarter to $30.3B.
Based on William Blair Investment Management's 13F filing for Q1 2026, filed 8 May 2026.