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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
+788.31%
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 | |
|---|---|---|---|---|---|---|
76
Doximity
DOCS
$4.88B
| $113M | 0.37% |
4,834,220
-622,765
| -11% | -$19.4M |
|
|
77
Synaptics
SYNA
$4.15B
| $111M | 0.37% |
+1,586,244
| New | +$129M |
|
78
National Vision
EYE
$1.81B
| $109M | 0.36% |
4,225,766
-285,129
| -6% | -$7.75M |
|
79
Planet Fitness
PLNT
$3.78B
| $108M | 0.36% |
1,452,642
-6,653
| -0.5% | -$585K |
|
80
Diebold Nixdorf
DBD
$2.56B
| $108M | 0.36% |
1,426,464
-376,107
| -21% | -$27.7M |
|
81
Freshpet
FRPT
$3.22B
| $107M | 0.35% |
1,813,185
-139,582
| -7% | -$9.81M |
|
82
Millicom
TIGO
$16.3B
| $105M | 0.35% |
1,405,608
+1,280,433
| +1,023% | +$84M |
|
83
Krystal Biotech
KRYS
$9.66B
| $105M | 0.35% |
407,178
+30,838
| +8% | +$8.21M |
|
84
Garrett Motion
GTX
$5.57B
| $105M | 0.35% |
5,762,697
-296,590
| -5% | -$5.53M |
|
85
Verisk Analytics
VRSK
$25B
| $104M | 0.34% |
547,504
+147,953
| +37% | +$30M |
|
86
Littelfuse
LFUS
$11.6B
| $103M | 0.34% |
+304,575
| New | +$98.9M |
|
87
AppFolio
APPF
$7.04B
| $102M | 0.34% |
643,231
+4,990
| +0.8% | +$945K |
|
88
Casella Waste Systems
CWST
$5.69B
| $99.7M | 0.33% |
1,257,092
-211,114
| -14% | -$20.2M |
|
89
Churchill Downs
CHDN
$6.12B
| $98.2M | 0.32% |
1,093,389
-52,024
| -5% | -$4.94M |
|
90
National Bank Holdings
NBHC
$1.9B
| $96.9M | 0.32% |
+2,474,861
| New | +$99.2M |
|
91
Novanta
NOVT
$6.29B
| $92.5M | 0.31% |
783,084
-125,822
| -14% | -$16.5M |
|
92
Birkenstock
BIRK
$7.07B
| $92.3M | 0.3% |
+2,575,402
| New | +$100M |
|
93
Alignment Healthcare
ALHC
$2.98B
| $91.9M | 0.3% |
5,214,614
+2,909,359
| +126% | +$58.4M |
|
94
Pool Corp
POOL
$7.5B
| $91.5M | 0.3% |
452,273
-67,563
| -13% | -$15.9M |
|
95
StepStone Group
STEP
$3.82B
| $91.4M | 0.3% |
1,914,477
+1,244,285
| +186% | +$71.9M |
|
96
Advanced Drainage Systems
WMS
$10.9B
| $89.9M | 0.3% |
655,684
-32,363
| -5% | -$5.01M |
|
97
Kennametal
KMT
$2.52B
| $89.7M | 0.3% |
+2,482,535
| New | +$90.5M |
|
98
Guardant Health
GH
$22.6B
| $87.9M | 0.29% |
+951,114
| New | +$95.5M |
|
99
Old National Bancorp
ONB
$10.2B
| $86.1M | 0.28% |
3,894,798
-2,063,138
| -35% | -$48.2M |
|
100
Fabrinet
FN
$20.1B
| $86M | 0.28% |
164,830
-35,494
| -18% | -$18M |
|
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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.