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William Blair & Company

William Blair & Company Portfolio holdings

AUM $34.9B
1-Year Est. Return 18.88%
This Fund
S&P 500
This Quarter Est. Return
-3.16%
1 Year Est. Return
+18.88%
3 Year Est. Return
+73.84%
5 Year Est. Return
+90.13%
10 Year Est. Return
+512.03%
AUM
$34.9B
AUM Growth
-$2.36B
Cap. Flow
-$465K
Cap. Flow %
-0%
Top 10 Hldgs %
25.64%
Holding
2,019
New
132
Increased
799
Reduced
746
Closed
97

Top Buys

Rank Stock Value
1
RSP icon
Invesco S&P 500 Equal Weight ETF
RSP
+$224M
2
VEU icon
Vanguard FTSE All-World ex-US ETF
VEU
+$113M
3
PWR icon
Quanta Services
PWR
+$75M
4
GLD icon
SPDR Gold Trust
GLD
+$58.9M
5
BA icon
Boeing
BA
+$55.5M

Top Sells

Rank Stock Value
1
WDAY icon
Workday
WDAY
+$91.2M
2
CWAN
Clearwater Analytics
CWAN
+$78M
3
APP icon
Applovin
APP
+$74.7M
4
TYL icon
Tyler Technologies
TYL
+$69.1M
5
UBER icon
Uber
UBER
+$62.2M

Sector Composition

Rank Sector Weight
1 Technology 21.79%
2 Industrials 14.2%
3 Financials 12.26%
4 Healthcare 10.59%
5 Consumer Discretionary 7.17%
Name Market Value Portfolio Weight Shares or Principal Change
in Stake 		Capital Flow
ITOT icon
101
iShares Core S&P Total US Stock Market ETF
ITOT
$93.3B
$82.3M 0.24%
577,496
+36,696
+7% +$5.46M
AMT icon
102
American Tower
AMT
$82.5B
$81.1M 0.23%
470,128
-208,116
-31% -$37.4M
TYL icon
103
Tyler Technologies
TYL
$13.7B
$77.8M 0.22%
227,378
-185,480
-45% -$69.1M
SHOP icon
104
Shopify
SHOP
$170B
$74.4M 0.21%
627,424
+16,691
+3% +$2.19M
RTX icon
105
RTX Corp
RTX
$298B
$74.2M 0.21%
384,627
+7,825
+2% +$1.56M
IUSG icon
106
iShares Core S&P US Growth ETF
IUSG
$30.8B
$74.2M 0.21%
478,278
+58,584
+14% +$9.64M
IRTC icon
107
iRhythm Holdings
IRTC
$3.77B
$74.2M 0.21%
628,385
-90,412
-13% -$13M
CRM icon
108
Salesforce
CRM
$149B
$72.6M 0.21%
389,008
-163,078
-30% -$33.8M
VRSK icon
109
Verisk Analytics
VRSK
$28.1B
$72.1M 0.21%
380,106
-6,214
-2% -$1.26M
IWV icon
110
iShares Russell 3000 ETF
IWV
$19.4B
$72M 0.21%
194,240
-4,431
-2% -$1.71M
MRVL icon
111
Marvell Technology
MRVL
$153B
$71.7M 0.21%
723,976
+228,898
+46% +$19.2M
WAB icon
112
Wabtec
WAB
$51B
$70.9M 0.2%
283,859
-11,092
-4% -$2.68M
MCK icon
113
McKesson
MCK
$103B
$69.3M 0.2%
80,042
+51,170
+177% +$45.7M
GNRC icon
114
Generac Holdings
GNRC
$11.1B
$67.7M 0.19%
346,830
+41,181
+13% +$7.91M
HON icon
115
Honeywell
HON
$78.8B
$66.9M 0.19%
295,831
+26,470
+10% +$6.05M
MDB icon
116
MongoDB
MDB
$24B
$66.3M 0.19%
270,982
-22,904
-8% -$7.66M
INTU icon
117
Intuit
INTU
$87.4B
$66M 0.19%
152,554
-91,321
-37% -$43.6M
ACN icon
118
Accenture
ACN
$102B
$64.7M 0.19%
326,073
-76,126
-19% -$17.7M
CSCO icon
119
Cisco
CSCO
$451B
$63.9M 0.18%
823,801
+4,898
+0.6% +$383K
TJX icon
120
TJX Companies
TJX
$178B
$63M 0.18%
394,646
+66,970
+20% +$10.4M
QCOM icon
121
Qualcomm
QCOM
$175B
$62.7M 0.18%
486,969
-56,023
-10% -$8.18M
ULS icon
122
UL Solutions
ULS
$18.3B
$62.2M 0.18%
725,672
-115,896
-14% -$9.14M
SPGI icon
123
S&P Global
SPGI
$124B
$60.9M 0.17%
143,223
-68,110
-32% -$31.6M
LOW icon
124
Lowe's Companies
LOW
$123B
$60.6M 0.17%
256,414
-49,105
-16% -$12.8M
CME icon
125
CME Group
CME
$94.1B
$60.4M 0.17%
204,534
+56,694
+38% +$16.8M
3 4
5
6 7

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William Blair & Company's Q1 2026 Portfolio in Review

As of Q1 2026, William Blair & Company held 2,019 positions worth $34.9B, down 6.3% from $37.3B the previous quarter. Its ten largest holdings account for 26% of the portfolio.

William Blair & Company's Q1 2026 filing shows 132 new, 799 increased, 746 reduced and 97 closed positions. Its largest new stake was Silicon Motion: 103,179 shares worth $11.6M. The largest sale was Workday, an estimated $91.2M.

By sector, the portfolio is most concentrated in Technology at 22% of assets, down from 26% a quarter earlier, followed by Industrials and Financials.

  • William Blair & Company's largest Q1 2026 buy was Silicon Motion: 103,179 shares worth $11.6M.
  • William Blair & Company added most to Invesco S&P 500 Equal Weight ETF in Q1 2026, an estimated $224M increase.
  • William Blair & Company's biggest Q1 2026 reduction was Workday, cutting an estimated $91.2M.
  • William Blair & Company fully exited Dynavax Technologies in Q1 2026, selling an estimated $27.4M.
  • William Blair & Company's ten largest holdings make up 26% of its $34.9B portfolio in Q1 2026.
  • William Blair & Company opened 132 new positions and closed 97 in Q1 2026.
  • William Blair & Company's portfolio value fell 6.3% quarter-over-quarter to $34.9B.

Based on William Blair & Company's 13F filing for Q1 2026, filed 8 May 2026.