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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 | |
|---|---|---|---|---|---|---|
1
NVIDIA
NVDA
$5.42T
| $1.98B | 5.53% |
10,628,667
-940,334
| -8% | -$175M |
|
2
TSMC
TSM
$2.18T
| $1.82B | 5.07% |
5,985,330
-436,828
| -7% | -$128M |
|
3
Microsoft
MSFT
$3.71T
| $1.69B | 4.71% |
3,490,302
-346,524
| -9% | -$174M |
|
4
Apple
AAPL
$4.57T
| $1.48B | 4.13% |
5,444,328
-176,125
| -3% | -$47.3M |
|
5
Amazon
AMZN
$2.96T
| $1.01B | 2.82% |
4,387,003
-34,158
| -0.8% | -$7.81M |
|
|
6
Alphabet (Google) Class A
GOOGL
$4.33T
| $988M | 2.75% |
3,154,973
+668,971
| +27% | +$191M |
|
7
Broadcom
AVGO
$2.04T
| $878M | 2.45% |
2,536,611
-274,513
| -10% | -$98.2M |
|
8
Meta Platforms (Facebook)
META
$1.51T
| $783M | 2.19% |
1,186,769
+642
| +0.1% | +$429K |
|
9
Mastercard
MA
$493B
| $619M | 1.73% |
1,084,947
-20,398
| -2% | -$11.4M |
|
10
Carlyle Group
CG
$17.2B
| $422M | 1.18% |
7,131,902
-1,617,073
| -18% | -$91.9M |
|
11
TransUnion
TRU
$15.3B
| $340M | 0.95% |
3,965,495
-713,314
| -15% | -$58.6M |
|
12
Mercado Libre
MELI
$92.3B
| $334M | 0.93% |
165,579
-64,225
| -28% | -$135M |
|
13
ServiceNow
NOW
$129B
| $329M | 0.92% |
2,148,780
+278,730
| +15% | +$47.8M |
|
14
Nu Holdings
NU
$66.9B
| $313M | 0.87% |
18,699,367
-750,057
| -4% | -$12.1M |
|
15
Sea Limited
SE
$69.5B
| $302M | 0.84% |
2,370,876
-1,092,656
| -32% | -$162M |
|
16
Idexx Laboratories
IDXX
$46.2B
| $299M | 0.83% |
441,324
-17,695
| -4% | -$12.1M |
|
|
17
Snowflake
SNOW
$115B
| $295M | 0.82% |
1,346,998
+828,789
| +160% | +$202M |
|
18
Intuit
INTU
$89B
| $293M | 0.82% |
442,391
-44,841
| -9% | -$29.6M |
|
19
Monster Beverage
MNST
$88.5B
| $288M | 0.8% |
3,761,249
+761,531
| +25% | +$54.6M |
|
20
Advanced Micro Devices
AMD
$789B
| $287M | 0.8% |
1,339,546
+292,346
| +28% | +$65.7M |
|
21
Costco
COST
$420B
| $283M | 0.79% |
328,468
+5,728
| +2% | +$5.19M |
|
22
Agilent Technologies
A
$41.2B
| $281M | 0.78% |
2,063,009
-81,077
| -4% | -$11.7M |
|
23
Linde
LIN
$226B
| $274M | 0.77% |
643,470
+106,059
| +20% | +$45.4M |
|
24
Onto Innovation
ONTO
$15.3B
| $273M | 0.76% |
1,726,587
-255,174
| -13% | -$36.2M |
|
25
O'Reilly Automotive
ORLY
$76.3B
| $272M | 0.76% |
2,981,507
+65,833
| +2% | +$6.43M |
|
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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.