Stocks/Funds/CIK 1644956

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC

long-term holder
Quarterly 13F filings · Latest period 2026-03-31 · CIK 1644956
Assets
$30.11B
-15.0% YoY
Holdings
412
Lifetime alpha vs market
-1.59% annual
Average hold time
3.8 yr
median 3.0 yr

Quarterly history

Cum return +216% vs S&P +272% · α -56% lifetimeAUM $30.1B · peak $40.8BFlow $-3.8B (-11%)2016-062017-122019-062020-122022-062023-122025-062026-03
AUM ($B)fundS&P 500(gap = α)/ Flow in/out

Behavior signals (lifetime)

Dip response
-6.54%
trims when stocks drop
when a holding falls −10%+
Middle response
-5.43%
baseline attrition
Rally response
-8.77%
trims into rallies
when a holding rises +10%+

Top positions · 30

Ticker$ value% portYoYHold time
TSMTaiwan Semiconductor Man$1.87B6.2%+105.6%10.5 yr
NVDANVIDIA Corporation$1.56B5.2%+60.9%5.0 yr
AAPLApple Inc.$1.22B4.1%+14.7%3.8 yr
MSFTMicrosoft Corporation$1.07B3.6%-0.6%10.5 yr
GOOGLAlphabet Inc.$720M2.4%10.5 yr
AVGOBroadcom Inc.$681M2.3%+86.0%2.0 yr
AMZNAmazon.com, Inc.$659M2.2%+9.5%10.5 yr
METAMeta Platforms, Inc.$580M1.9%-0.4%10.5 yr
MAMastercard Incorporated$530M1.8%-8.5%10.5 yr
AZNAstraZeneca PLC$377M1.3%+36.2%0.3 yr
LINLinde plc$315M1.0%+7.9%3.3 yr
CGThe Carlyle Group Inc.$305M1.0%+13.9%3.5 yr
COSTCostco Wholesale Corpora$301M1.0%+5.9%10.5 yr
ITUBItaú Unibanco Holding S$266M0.9%+64.3%7.0 yr
TWSTTwist Bioscience Corpora$250M0.8%+21.0%6.3 yr

Portfolio composition (YoY)

Industry mix
Semiconductors17.3%+7.3pp$5.21B
Software - Infrastructure5.0%-1.2pp$1.50B
Consumer Electronics4.7%+1.4pp$1.42B
Software - Application4.5%-4.5pp$1.37B
Internet Content & Information4.5%+1.0pp$1.35B
Specialty Retail4.3%-3.1pp$1.30B
Banks - Regional4.0%+0.3pp$1.20B
Biotechnology3.4%+1.9pp$1.02B
Industrial - Machinery2.5%+1.0pp$758M
Hardware, Equipment & Parts2.5%+1.5pp$743M
Country
US81.5%+1.0pp
TW6.2%+2.7pp
GB2.9%+1.6pp
BR1.5%+1.1pp
CA1.2%-0.3pp
Unknown1.2%-1.4pp
PE0.8%+0.5pp
NL0.7%+0.6pp
Top 5: 21.4% · Top 10: 30.8% · Top 25: 42.9%

Winners

TickerPrev $PnLYoY %
TSM$1.22B+1.28B105.6%
NVDA$1.32B+0.81B60.9%
AVGO$515M+0.44B86.0%
AAPL$1.16B+0.17B14.7%
AMZN$1.16B+0.11B9.5%

Losers

TickerPrev $PnLYoY %
PRMB$405M-0.18B-45.9%
INTU$353M-0.10B-29.3%
MA$666M-0.06B-8.5%
TRU$278M-0.04B-16.1%
NOW$292M-0.02B-34.3%

Top buys this quarter · 15

AZN AstraZeneca PLCnew+$383M
BWA BorgWarner Inc.+$156M
APH Amphenol Corporationnew+$136M
POWI Power Integrations, Inc.+$122M
STRL Sterling Infrastructure, Inc.+$115M
SYNA Synaptics Incorporatednew+$111M
CHRW C.H. Robinson Worldwide, Inc.+$100M
NBHC National Bank Holdings Corpora+$96M
TIGO Millicom International Cellula+$94M
LOPE Grand Canyon Education, Inc.+$90M

Top sells this quarter · 15

NVDA NVIDIA Corporation$294M
CIEN Ciena Corporation$272M
AMZN Amazon.com, Inc.$255M
MSFT Microsoft Corporation$220M
TER Teradyne, Inc.exit$203M
SE Sea Limitedexit$196M
ORCL Oracle Corporation$176M
AAPL Apple Inc.$160M
TSM Taiwan Semiconductor Manufactu$1.82B
MELI MercadoLibre, Inc.$157M

Quarterly history (TTM returns)

PeriodAUM# PosReturn (1yr)SPY (1yr)Alpha (1yr)Flow
2026-03-31$30.11B412+15.87%+17.59%-1.72%-3.83B
2025-12-31$35.64B412+10.91%+17.72%-6.81%-3.13B
2025-09-30$38.45B413+11.68%+17.52%-5.84%-1.72B
2025-06-30$37.51B416+11.04%+14.94%-3.90%-2.43B
2025-03-31$35.45B422-4.18%+8.30%-12.48%-1.73B
2024-12-31$40.77B432+13.40%+24.89%-11.49%-0.20B
2024-09-30$40.36B411+27.49%+36.04%-8.54%+0.01B
2024-06-30$37.89B410+14.01%+24.49%-10.48%+0.38B
2024-03-31$38.57B409+25.62%+29.62%-4.01%+1.64B
2023-12-31$34.23B405+25.17%+26.18%-1.01%+0.05B
2023-09-30$29.95B396+17.55%+21.57%-4.02%+0.38B
2023-06-30$31.06B393+24.11%+19.42%+4.68%+0.42B
2023-03-31$28.60B391-7.41%-7.82%+0.41%+0.61B
2022-12-31$26.04B399-17.85%-18.17%+0.32%-0.97B
2022-09-30$25.20B385-14.87%-15.51%+0.64%-1.83B
2022-06-30$26.88B398-14.84%-10.62%-4.22%+0.23B