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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
+3.11%
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
$35.9B
AUM Growth
-$2.82B
(-7.3%)
Cap. Flow
-$3B
Cap. Flow
% of AUM
-8.37%
Top 10 Holdings %
Top 10 Hldgs %
32.55%
Holding
459
New
45
Increased
106
Reduced
259
Closed
46
Top Buys
| Rank | Stock | Value |
|---|---|---|
| 1 |
Snowflake
SNOW
|
+$202M |
| 2 |
argenx
ARGX
|
+$191M |
| 3 |
Alphabet (Google) Class A
GOOGL
|
+$191M |
| 4 |
HealthEquity
HQY
|
+$178M |
| 5 |
F5
FFIV
|
+$148M |
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
Lam Research
LRCX
|
+$270M |
| 2 |
Ciena
CIEN
|
+$260M |
| 3 |
Uber
UBER
|
+$233M |
| 4 |
Live Nation Entertainment
LYV
|
+$229M |
| 5 |
Stride
LRN
|
+$225M |
Sector Composition
| Rank | Sector | Weight |
|---|---|---|
| 1 | Technology | 37.93% |
| 2 | Financials | 12.94% |
| 3 | Healthcare | 12.67% |
| 4 | Consumer Discretionary | 10.8% |
| 5 | Industrials | 9.43% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
26
Itaú Unibanco
ITUB
$82.7B
| $262M | 0.73% |
36,551,763
+6,197,462
| +20% | +$44.1M |
|
|
27
Ciena
CIEN
$54.9B
| $257M | 0.72% |
1,098,593
-1,342,295
| -55% | -$260M |
|
28
UnitedHealth
UNH
$361B
| $252M | 0.7% |
762,243
-6,292
| -0.8% | -$2.13M |
|
|
P
29
Everpure Inc
P
$36.4B
| $251M | 0.7% |
3,742,928
-923,964
| -20% | -$77.2M |
|
30
Oracle
ORCL
$419B
| $245M | 0.68% |
1,256,536
+148,950
| +13% | +$35.5M |
|
31
Doximity
DOCS
$4.65B
| $242M | 0.67% |
5,456,985
-372,184
| -6% | -$20.9M |
|
32
Tyler Technologies
TYL
$13.2B
| $225M | 0.63% |
495,297
+36,183
| +8% | +$17.2M |
|
33
Credicorp
BAP
$30B
| $220M | 0.61% |
767,413
-52,660
| -6% | -$13.9M |
|
34
Globus Medical
GMED
$11.4B
| $220M | 0.61% |
2,519,782
-299,383
| -11% | -$22.7M |
|
|
TLN
35
Talen Energy Corp
TLN
$17.1B
| $213M | 0.6% |
569,399
-110,298
| -16% | -$42.9M |
|
36
Insmed
INSM
$29B
| $213M | 0.59% |
1,221,096
-333,961
| -21% | -$60.9M |
|
|
PRMB
37
Primo Brands
PRMB
$8.55B
| $206M | 0.58% |
12,627,420
+793,036
| +7% | +$14.7M |
|
38
Madrigal Pharmaceuticals
MDGL
$12.4B
| $206M | 0.58% |
354,220
-57,582
| -14% | -$29.4M |
|
39
Mueller Industries
MLI
$15.1B
| $204M | 0.57% |
3,559,812
-429,938
| -11% | -$23.1M |
|
40
Everest Group
EG
$14B
| $198M | 0.55% |
584,301
-67,173
| -10% | -$22.2M |
|
41
Veeva Systems
VEEV
$38.4B
| $197M | 0.55% |
881,223
+132,579
| +18% | +$35.2M |
|
42
Q2 Holdings
QTWO
$3.95B
| $194M | 0.54% |
2,694,718
+553,713
| +26% | +$38M |
|
43
BWX Technologies
BWXT
$15.5B
| $191M | 0.53% |
1,107,600
-147,710
| -12% | -$27.7M |
|
44
Twist Bioscience
TWST
$7.72B
| $189M | 0.53% |
5,954,429
+1,812,146
| +44% | +$56.5M |
|
|
45
argenx
ARGX
$54.1B
| $188M | 0.52% |
+223,666
| New | +$191M |
|
|
BWIN
46
Baldwin Insurance Group
BWIN
$2.88B
| $181M | 0.51% |
7,543,813
+2,439,118
| +48% | +$62.1M |
|
47
Cameco
CCJ
$43B
| $181M | 0.51% |
1,980,827
-657,206
| -25% | -$59.2M |
|
48
Brink's
BCO
$4.69B
| $180M | 0.5% |
1,544,641
-225,226
| -13% | -$25.8M |
|
49
Copart
CPRT
$27.2B
| $180M | 0.5% |
4,585,833
-65,641
| -1% | -$2.72M |
|
|
WAY
50
Waystar Holding Corp
WAY
$4.66B
| $173M | 0.48% |
5,282,220
+19,033
| +0.4% | +$678K |
|
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William Blair Investment Management's Q4 2025 Portfolio in Review
As of Q4 2025, William Blair Investment Management held 459 positions worth $35.9B, down 7.3% from $38.7B the previous quarter. Its ten largest holdings account for 33% of the portfolio.
William Blair Investment Management withdrew a net $3B in Q4 2025, closing 46 positions and reducing 259 holdings. Its most notable exit was Live Nation Entertainment, an estimated $229M position sold in full.
By sector, the portfolio is most concentrated in Technology at 38% of assets, down from 39% a quarter earlier, followed by Financials and Healthcare.
Against the trend, William Blair Investment Management opened a new position in argenx worth $188M.
- William Blair Investment Management's largest Q4 2025 buy was argenx: 223,666 shares worth $188M.
- William Blair Investment Management added most to Snowflake in Q4 2025, an estimated $202M increase.
- William Blair Investment Management's biggest Q4 2025 reduction was Lam Research, cutting an estimated $270M.
- William Blair Investment Management fully exited Live Nation Entertainment in Q4 2025, selling an estimated $229M.
- William Blair Investment Management's ten largest holdings make up 33% of its $35.9B portfolio in Q4 2025.
- William Blair Investment Management opened 45 new positions and closed 46 in Q4 2025.
- William Blair Investment Management's portfolio value fell 7.3% quarter-over-quarter to $35.9B.
Based on William Blair Investment Management's 13F filing for Q4 2025, filed 9 Feb 2026.