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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
CWST icon
226
Casella Waste Systems
CWST
$5.88B
$23M 0.07%
290,464
+11,343
+4% +$1.09M
IRM icon
227
Iron Mountain
IRM
$36.6B
$23M 0.07%
225,249
-13,036
-5% -$1.3M
FISV
228
Fiserv Inc
FISV
$29.4B
$22.7M 0.07%
407,135
-161,449
-28% -$9.99M
XLV icon
229
State Street Health Care Select Sector SPDR ETF
XLV
$43.3B
$22.4M 0.06%
152,963
+18,976
+14% +$2.93M
ESGD icon
230
iShares ESG Aware MSCI EAFE ETF
ESGD
$11.7B
$22.1M 0.06%
231,547
+18,135
+8% +$1.79M
COF icon
231
Capital One
COF
$129B
$22.1M 0.06%
121,300
-8,542
-7% -$1.79M
VGT icon
232
Vanguard Information Technology ETF
VGT
$135B
$22M 0.06%
251,968
-14,712
-6% -$1.35M
CEG icon
233
Constellation Energy
CEG
$92.7B
$21.8M 0.06%
77,925
+13,222
+20% +$4.02M
XLK icon
234
State Street Technology Select Sector SPDR ETF
XLK
$111B
$21.7M 0.06%
163,656
-50,241
-23% -$7.08M
C icon
235
Citigroup
C
$215B
$21.3M 0.06%
187,663
+3,001
+2% +$342K
EQIX icon
236
Equinix
EQIX
$101B
$21.3M 0.06%
21,686
+500
+2% +$445K
LMT icon
237
Lockheed Martin
LMT
$133B
$21.2M 0.06%
35,133
-489
-1% -$301K
DIA icon
238
State Street SPDR Dow Jones Industrial Average ETF Trust
DIA
$45.4B
$20.6M 0.06%
44,559
+7,298
+20% +$3.54M
VXUS icon
239
Vanguard Total International Stock ETF
VXUS
$152B
$20.6M 0.06%
266,928
+98,356
+58% +$7.81M
NKE icon
240
Nike
NKE
$63.6B
$20.5M 0.06%
388,727
+249,624
+179% +$15.1M
EQT icon
241
EQT Corp
EQT
$33B
$20.4M 0.06%
321,192
+5,826
+2% +$341K
FSV icon
242
FirstService
FSV
$6.62B
$20.3M 0.06%
146,314
+3,252
+2% +$495K
SPHQ icon
243
Invesco S&P 500 Quality ETF
SPHQ
$19.3B
$20.2M 0.06%
269,028
+18,191
+7% +$1.41M
UNH icon
244
UnitedHealth
UNH
$387B
$20.2M 0.06%
74,523
-28,339
-28% -$8.44M
EHC icon
245
Encompass Health
EHC
$11.4B
$20M 0.06%
207,242
-6,297
-3% -$646K
AZN icon
246
AstraZeneca
AZN
$271B
$19.8M 0.06%
100,622
-4,970
-5% -$958K
RCL icon
247
Royal Caribbean
RCL
$87.2B
$19.7M 0.06%
71,756
+3,668
+5% +$1.09M
KMI icon
248
Kinder Morgan
KMI
$71.6B
$19.6M 0.06%
585,339
-8,432
-1% -$263K
HWM icon
249
Howmet Aerospace
HWM
$112B
$19.6M 0.06%
85,139
+1,204
+1% +$281K
NVS icon
250
Novartis
NVS
$302B
$19.3M 0.06%
126,421
+45,143
+56% +$6.92M
8 9
10
11 12

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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.