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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
IWM icon
51
iShares Russell 2000 ETF
IWM
$80.3B
$156M 0.45%
628,228
+69,490
+12% +$17.9M
CVX icon
52
Chevron
CVX
$378B
$148M 0.42%
715,986
+49,527
+7% +$9.03M
VIG icon
53
Vanguard Dividend Appreciation ETF
VIG
$112B
$148M 0.42%
687,771
+14,217
+2% +$3.17M
GWRE icon
54
Guidewire Software
GWRE
$12.4B
$146M 0.42%
975,296
-159,255
-14% -$24.2M
ANET icon
55
Arista Networks
ANET
$215B
$141M 0.41%
1,151,227
+26,667
+2% +$3.57M
ABT icon
56
Abbott
ABT
$182B
$136M 0.39%
1,327,761
-250,038
-16% -$28.2M
AON icon
57
Aon
AON
$78.4B
$136M 0.39%
421,605
-74,702
-15% -$24.8M
BX icon
58
Blackstone
BX
$106B
$136M 0.39%
1,178,612
-190,433
-14% -$24.8M
CPRT icon
59
Copart
CPRT
$27.6B
$135M 0.39%
4,070,990
-343,984
-8% -$12.9M
AAON icon
60
Aaon
AAON
$8.27B
$134M 0.38%
1,622,203
-56,822
-3% -$5.16M
GS icon
61
Goldman Sachs
GS
$309B
$132M 0.38%
156,265
+1,262
+0.8% +$1.13M
PG icon
62
Procter & Gamble
PG
$346B
$129M 0.37%
893,933
+24,965
+3% +$3.78M
IBM icon
63
IBM
IBM
$204B
$126M 0.36%
518,457
+47,010
+10% +$12.7M
UNP icon
64
Union Pacific
UNP
$178B
$125M 0.36%
514,829
+44,455
+9% +$10.9M
PWR icon
65
Quanta Services
PWR
$93.1B
$124M 0.36%
225,850
+145,549
+181% +$75M
DXCM icon
66
DexCom
DXCM
$28.3B
$121M 0.35%
1,927,387
-61,454
-3% -$4.28M
ROL icon
67
Rollins
ROL
$18.8B
$121M 0.35%
2,265,013
+4,255
+0.2% +$253K
VTI icon
68
Vanguard Total Stock Market ETF
VTI
$655B
$119M 0.34%
372,371
+34,241
+10% +$11.5M
IUSV icon
69
iShares Core S&P US Value ETF
IUSV
$27.3B
$119M 0.34%
1,165,952
+71,953
+7% +$7.55M
RBC icon
70
RBC Bearings
RBC
$18.5B
$118M 0.34%
217,833
-4,402
-2% -$2.34M
LIN icon
71
Linde
LIN
$234B
$116M 0.33%
233,182
-584
-0.2% -$276K
CW icon
72
Curtiss-Wright
CW
$27.5B
$114M 0.33%
167,027
+10,026
+6% +$6.67M
IWF icon
73
iShares Russell 1000 Growth ETF
IWF
$120B
$113M 0.33%
1,064,104
+12,032
+1% +$1.37M
MU icon
74
Micron Technology
MU
$1.02T
$112M 0.32%
332,311
+32,341
+11% +$12.7M
WM icon
75
Waste Management
WM
$95.5B
$111M 0.32%
484,303
-14,745
-3% -$3.39M
1 2
3
4 5

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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.