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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 | |
|---|---|---|---|---|---|---|
226
Kirby Corp
KEX
$7.7B
| $25M | 0.08% |
187,892
-116,319
| -38% | -$14.7M |
|
227
Graham Corp
GHM
$1.18B
| $24.8M | 0.08% |
314,301
+16,281
| +5% | +$1.28M |
|
228
CarGurus
CARG
$3.17B
| $24.7M | 0.08% |
724,299
+156,985
| +28% | +$5.14M |
|
|
MDA
229
MDA Space Ltd
MDA
$4.81B
| $24.4M | 0.08% |
+963,494
| New | +$28.3M |
|
230
Ryanair
RYAAY
$30B
| $24.3M | 0.08% |
420,246
+369,378
| +726% | +$24.4M |
|
231
McGrath RentCorp
MGRC
$2.91B
| $24.2M | 0.08% |
+219,784
| New | +$24.4M |
|
232
Atmus Filtration Technologies
ATMU
$4.32B
| $24.2M | 0.08% |
426,072
-255,900
| -38% | -$15.1M |
|
233
Centuri Holdings
CTRI
$2.72B
| $24.2M | 0.08% |
827,449
+26,127
| +3% | +$761K |
|
234
Ecovyst
ECVT
$1.34B
| $24M | 0.08% |
1,864,621
-864,128
| -32% | -$9.76M |
|
235
La-Z-Boy
LZB
$1.61B
| $23.9M | 0.08% |
744,481
+25,235
| +4% | +$912K |
|
236
Live Oak Bancshares
LOB
$1.95B
| $23.9M | 0.08% |
722,897
+74,336
| +11% | +$2.74M |
|
237
Mercury Systems
MRCY
$6.16B
| $23.9M | 0.08% |
327,288
-656,985
| -67% | -$57.2M |
|
238
Taylor Morrison
TMHC
| $23.8M | 0.08% |
408,605
+13,880
| +4% | +$867K |
|
239
Trex
TREX
$4.53B
| $23.6M | 0.08% |
+647,178
| New | +$26M |
|
240
Intercorp Financial Services
IFS
$6.63B
| $23.4M | 0.08% |
465,726
+18,839
| +4% | +$895K |
|
241
Equity Lifestyle Properties
ELS
$12.7B
| $23.1M | 0.08% |
370,369
-225,990
| -38% | -$14.6M |
|
242
Applied Industrial Technologies
AIT
$12.8B
| $22.9M | 0.08% |
86,263
-51,740
| -37% | -$14.1M |
|
243
Constellium
CSTM
$3.94B
| $22.6M | 0.07% |
+918,090
| New | +$21.8M |
|
244
Motorola Solutions
MSI
$70.5B
| $22.5M | 0.07% |
51,961
+31,429
| +153% | +$13.6M |
|
245
Healthcare Realty
HR
$7.47B
| $22.3M | 0.07% |
1,315,096
-819,484
| -38% | -$14.4M |
|
246
East-West Bancorp
EWBC
$17.9B
| $22.2M | 0.07% |
207,901
-122,933
| -37% | -$13.9M |
|
247
First Bancorp
FBNC
$2.61B
| $22.1M | 0.07% |
392,412
+13,274
| +4% | +$757K |
|
248
Belden
BDC
$4.04B
| $21.9M | 0.07% |
190,528
-24,625
| -11% | -$3.1M |
|
|
JBTM
249
JBT Marel
JBTM
$7.29B
| $21.5M | 0.07% |
168,115
-101,597
| -38% | -$15.4M |
|
250
Sylvamo
SLVM
$1.5B
| $21M | 0.07% |
498,331
-203,166
| -29% | -$9.51M |
|
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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.