William Blair Investment Management 13F Holdings & Latest Moves

13F filer · Latest filing May 8, 2026 · SEC CIK 0001644956

William Blair Investment Management reported a 13F portfolio worth $30.26B as of Q1 2026. Latest 13F moves (filed May 8, 2026): 5 new positions, 16 added, 43 reduced. Largest change by value: reduced $TSM ($2.64B held).

13F value (Q1 2026)
$30.26B
New positions
5
Added / reduced
16 / 43
Sold out
0

Top buys and sells in the latest 13F

Biggest new and added positions

FiledTicker MoveChangeShares heldValue held1W1M6MStory
$AZN Added +1.90M (+4027.06%) 1.94M $368.27M -0.7%-0.7% —
$AZN Added +1.90M (+4027.06%) 1.94M $354.02M -0.7%-0.7% —
$PRMB Added +428.77K (+3.40%) 13.06M $319.09M —
$PRMB Added +428.77K (+3.40%) 13.06M $307.34M —
$MLI Added +329.82K (+18.53%) 2.11M $291.33M -3.1%-5.1% —

Biggest reduced and exited positions

FiledTicker MoveChangeShares heldValue held1W1M6MStory
$TSM Reduced -467.07K (-7.80%) 5.52M $2.64B -1.8%+3.7% —
$NVDA Reduced -1.69M (-15.87%) 8.94M $1.77B +4.7%-2.9% —
$AAPL Reduced -631.89K (-11.61%) 4.81M $1.38B +2.4%+2.9% —
$MSFT Reduced -593.52K (-17%) 2.90M $1.07B +1.6%-0.6% —
$GOOGL Reduced -650.37K (-20.61%) 2.50M $893.14M -1.0%-9.3% —

New positions in the latest 13F

FiledTicker MoveChangeShares heldValue held1W1M6MStory
$P New +2.88M 2.88M $227.03M +3.9%-5.6% —
$POWI New +2.38M 2.38M $199.41M -0.1%+4.9% Read
$SYNA New +1.59M 1.59M $197.06M +2.2%+8.4% —
$BWA New +2.88M 2.88M $196.43M +3.1%+24.0% —
$AKAM New +1.62M 1.62M $194.47M +2.1%-4.0% —

Added positions in the latest 13F

FiledTicker MoveChangeShares heldValue held1W1M6MStory
$AZN Added +1.90M (+4027.06%) 1.94M $368.27M -0.7%-0.7% —
$AZN Added +1.90M (+4027.06%) 1.94M $354.02M -0.7%-0.7% —
$PRMB Added +428.77K (+3.40%) 13.06M $319.09M —
$PRMB Added +428.77K (+3.40%) 13.06M $307.34M —
$MLI Added +329.82K (+18.53%) 2.11M $291.33M -3.1%-5.1% —
$STRL Added +282.17K (+683.97%) 323.42K $271.47M +0.5%+5.6% —
$FFIV Added +99.68K (+18.12%) 649.95K $270.35M +2.4%+11.9% —
$MLI Added +329.82K (+18.53%) 2.11M $259.14M -3.1%-5.1% —
$ARGX Added +42.40K (+18.96%) 266.07K $246.85M +2.2%+12.8% —
$ARGX Added +42.40K (+18.96%) 266.07K $239.18M +2.2%+12.8% —
$NOW Added +222.83K (+10.37%) 2.37M $232.12M +4.3%+25.2% —
$NXT Added +259.69K (+19.06%) 1.62M $209.41M +14.6%-0.2% —
$RRX Added +78.21K (+10.30%) 837.49K $199.48M -8.0%-1.9% Read
$HALO Added +683.02K (+37.06%) 2.53M $197.71M +4.7%+10.3% Read
$CHRW Added +604.16K (+138.09%) 1.04M $196.44M -4.6%+10.1% Read
$NXT Added +259.69K (+19.06%) 1.62M $194.18M +14.6%-0.2% Read

Reduced positions in the latest 13F

FiledTicker MoveChangeShares heldValue held1W1M6MStory
$TSM Reduced -467.07K (-7.80%) 5.52M $2.64B -1.8%+3.7% —
$NVDA Reduced -1.69M (-15.87%) 8.94M $1.77B +4.7%-2.9% —
$AAPL Reduced -631.89K (-11.61%) 4.81M $1.38B +2.4%+2.9% —
$MSFT Reduced -593.52K (-17%) 2.90M $1.07B +1.6%-0.6% —
$GOOGL Reduced -650.37K (-20.61%) 2.50M $893.14M -1.0%-9.3% —
$AVGO Reduced -335.05K (-13.21%) 2.20M $826.92M -1.1%-7.8% —
$AMZN Reduced -1.22M (-27.89%) 3.16M $760.98M -3.1%-10.1% —
$AMD Reduced -296.95K (-22.17%) 1.04M $588.95M -6.8%+7.7% —
$META Reduced -173.65K (-14.63%) 1.01M $570.68M +0.8%-4.0% —
$MA Reduced -24.30K (-2.24%) 1.06M $544.75M -0.3%-2.0% —
$TWST Reduced -684.71K (-11.50%) 5.27M $542.15M -13.5%+23.2% —
$TWST Reduced -684.71K (-11.50%) 5.27M $390.33M -13.5%+23.2% —
$ONTO Reduced -762.37K (-44.15%) 964.21K $368.03M -4.5%-5.5% —
$LIN Reduced -7.13K (-1.11%) 636.34K $330.22M +2.6%+2.1% —
$LIN Reduced -7.13K (-1.11%) 636.34K $327.99M +2.6%+2.1% —
$LSCC Reduced -81.54K (-3.84%) 2.04M $312.61M —
$LSCC Reduced -81.54K (-3.84%) 2.04M $290.18M —
$SNOW Reduced -219.47K (-16.29%) 1.13M $283.74M +3.3%+57.7% —
$COST Reduced -26K (-7.92%) 302.47K $282.95M +4.0%-3.4% —
$MNST Reduced -826K (-21.96%) 2.94M $282.14M +0.9%+2.5% —
$CG Reduced -830.79K (-11.65%) 6.30M $280.71M -5.2%-13.3% —
$UNH Reduced -88.98K (-11.67%) 673.26K $279.83M +3.7%+7.0% —
$MNST Reduced -826K (-21.96%) 2.94M $270.13M +0.9%+2.5% —
$CG Reduced -830.79K (-11.65%) 6.30M $265.34M -5.2%-13.3% —
$COHR Reduced -204.92K (-23.47%) 668.14K $263.56M +14.1%+19.9% —
$BAP Reduced -144.72K (-18.86%) 622.69K $242.59M -4.3%+1.4% —
$A Reduced -267.25K (-12.95%) 1.80M $236.75M -3.4%+14.8% —
$A Reduced -267.25K (-12.95%) 1.80M $233.18M -3.4%+14.8% —
$BAP Reduced -144.72K (-18.86%) 622.69K $229.39M -4.3%+1.4% —
$CRS Reduced -66.66K (-15.96%) 350.90K $216.45M -4.4%+16.7% —
$NVT Reduced -141.28K (-10.27%) 1.23M $209.28M -0.6%-3.6% —
$GTX Reduced -296.59K (-4.89%) 5.76M $208.78M +6.8%+11.5% Read
$TRU Reduced -1.07M (-27.09%) 2.89M $208.57M -8.0%-4.3% Read
$NVT Reduced -141.28K (-10.27%) 1.23M $204.63M -0.6%-3.6% Read
$ORLY Reduced -771.47K (-25.88%) 2.21M $203.52M -4.8%-4.2% —
$TLN Reduced -44.19K (-7.76%) 525.21K $201.82M -13.5%-5.6% Read
$ORLY Reduced -771.47K (-25.88%) 2.21M $199.25M -4.8%-4.2% Read
$CRS Reduced -66.66K (-15.96%) 350.90K $197.36M -4.4%+16.7% Read
$IDXX Reduced -89.70K (-20.33%) 351.62K $196.09M -5.6%+0.2% Read
$CAVA Reduced -25.28K (-1.04%) 2.39M $195.99M -3.2%-7.3% —
$BWXT Reduced -125.82K (-11.36%) 981.78K $194.30M -0.3%-8.6% Read
$IDXX Reduced -89.70K (-20.33%) 351.62K $193.92M -5.6%+0.2% —
$CIEN Reduced -700.01K (-63.72%) 398.58K $190.65M +1.2%-14.9% Read

All tracked 13F moves by William Blair Investment Management

FiledTicker MoveChangeShares heldValue held1W1M6MStory
$TLN Reduced -44.19K (-7.76%) 525.21K $201.82M -13.5%-5.6% Read
$TSM Reduced -467.07K (-7.80%) 5.52M $2.64B -1.8%+3.7% —
$MA Reduced -24.30K (-2.24%) 1.06M $544.75M -0.3%-2.0% —
$LSCC Reduced -81.54K (-3.84%) 2.04M $290.18M —
$LIN Reduced -7.13K (-1.11%) 636.34K $330.22M +2.6%+2.1% —
$LIN Reduced -7.13K (-1.11%) 636.34K $327.99M +2.6%+2.1% —
$LSCC Reduced -81.54K (-3.84%) 2.04M $312.61M —
$GTX Reduced -296.59K (-4.89%) 5.76M $208.78M +6.8%+11.5% Read
$COST Reduced -26K (-7.92%) 302.47K $282.95M +4.0%-3.4% —
$CAVA Reduced -25.28K (-1.04%) 2.39M $195.99M -3.2%-7.3% —
$SYNA New +1.59M 1.59M $197.06M +2.2%+8.4% —
$POWI New +2.38M 2.38M $199.41M -0.1%+4.9% Read
$P New +2.88M 2.88M $227.03M +3.9%-5.6% —
$BWA New +2.88M 2.88M $196.43M +3.1%+24.0% —
$AKAM New +1.62M 1.62M $194.47M +2.1%-4.0% —
$UNH Reduced -88.98K (-11.67%) 673.26K $279.83M +3.7%+7.0% —
$TWST Reduced -684.71K (-11.50%) 5.27M $390.33M -13.5%+23.2% —
$TWST Reduced -684.71K (-11.50%) 5.27M $542.15M -13.5%+23.2% —
$TRU Reduced -1.07M (-27.09%) 2.89M $208.57M -8.0%-4.3% Read
$CG Reduced -830.79K (-11.65%) 6.30M $265.34M -5.2%-13.3% —
$SNOW Reduced -219.47K (-16.29%) 1.13M $283.74M +3.3%+57.7% —
$ORLY Reduced -771.47K (-25.88%) 2.21M $199.25M -4.8%-4.2% Read
$ONTO Reduced -762.37K (-44.15%) 964.21K $368.03M -4.5%-5.5% —
$ORLY Reduced -771.47K (-25.88%) 2.21M $203.52M -4.8%-4.2% —
$NVT Reduced -141.28K (-10.27%) 1.23M $204.63M -0.6%-3.6% Read
$NVDA Reduced -1.69M (-15.87%) 8.94M $1.77B +4.7%-2.9% —
$NVT Reduced -141.28K (-10.27%) 1.23M $209.28M -0.6%-3.6% —
$MNST Reduced -826K (-21.96%) 2.94M $282.14M +0.9%+2.5% —
$MNST Reduced -826K (-21.96%) 2.94M $270.13M +0.9%+2.5% —
$MSFT Reduced -593.52K (-17%) 2.90M $1.07B +1.6%-0.6% —
$META Reduced -173.65K (-14.63%) 1.01M $570.68M +0.8%-4.0% —
$IDXX Reduced -89.70K (-20.33%) 351.62K $196.09M -5.6%+0.2% Read
$IDXX Reduced -89.70K (-20.33%) 351.62K $193.92M -5.6%+0.2% —
$CRS Reduced -66.66K (-15.96%) 350.90K $197.36M -4.4%+16.7% Read
$BAP Reduced -144.72K (-18.86%) 622.69K $242.59M -4.3%+1.4% —
$COHR Reduced -204.92K (-23.47%) 668.14K $263.56M +14.1%+19.9% —
$CIEN Reduced -700.01K (-63.72%) 398.58K $190.65M +1.2%-14.9% Read
$CG Reduced -830.79K (-11.65%) 6.30M $280.71M -5.2%-13.3% —
$CRS Reduced -66.66K (-15.96%) 350.90K $216.45M -4.4%+16.7% —
$BWXT Reduced -125.82K (-11.36%) 981.78K $194.30M -0.3%-8.6% Read
$AVGO Reduced -335.05K (-13.21%) 2.20M $826.92M -1.1%-7.8% —
$BAP Reduced -144.72K (-18.86%) 622.69K $229.39M -4.3%+1.4% —
$AAPL Reduced -631.89K (-11.61%) 4.81M $1.38B +2.4%+2.9% —
$AMZN Reduced -1.22M (-27.89%) 3.16M $760.98M -3.1%-10.1% —
$GOOGL Reduced -650.37K (-20.61%) 2.50M $893.14M -1.0%-9.3% —
$A Reduced -267.25K (-12.95%) 1.80M $236.75M -3.4%+14.8% —
$AMD Reduced -296.95K (-22.17%) 1.04M $588.95M -6.8%+7.7% —
$A Reduced -267.25K (-12.95%) 1.80M $233.18M -3.4%+14.8% —
$STRL Added +282.17K (+683.97%) 323.42K $271.47M +0.5%+5.6% —
$NOW Added +222.83K (+10.37%) 2.37M $232.12M +4.3%+25.2% —
$RRX Added +78.21K (+10.30%) 837.49K $199.48M -8.0%-1.9% Read
$PRMB Added +428.77K (+3.40%) 13.06M $307.34M —
$PRMB Added +428.77K (+3.40%) 13.06M $319.09M —
$NXT Added +259.69K (+19.06%) 1.62M $194.18M +14.6%-0.2% Read
$NXT Added +259.69K (+19.06%) 1.62M $209.41M +14.6%-0.2% —
$MLI Added +329.82K (+18.53%) 2.11M $259.14M -3.1%-5.1% —
$MLI Added +329.82K (+18.53%) 2.11M $291.33M -3.1%-5.1% —
$HALO Added +683.02K (+37.06%) 2.53M $197.71M +4.7%+10.3% Read
$FFIV Added +99.68K (+18.12%) 649.95K $270.35M +2.4%+11.9% —
$CHRW Added +604.16K (+138.09%) 1.04M $196.44M -4.6%+10.1% Read
$AZN Added +1.90M (+4027.06%) 1.94M $354.02M -0.7%-0.7% —
$AZN Added +1.90M (+4027.06%) 1.94M $368.27M -0.7%-0.7% —
$ARGX Added +42.40K (+18.96%) 266.07K $239.18M +2.2%+12.8% —
$ARGX Added +42.40K (+18.96%) 266.07K $246.85M +2.2%+12.8% —

13F reports are filed quarterly, up to 45 days after the quarter ends, so they show past holdings. 1W / 1M / 6M = how the stock moved after the filing.

Stocks William Blair Investment Management holds or traded

Frequently asked questions

What did William Blair Investment Management buy and sell in its latest 13F?

It opened or added to $AZN, $AZN, $PRMB, $PRMB and $MLI; it cut or exited $TSM, $NVDA, $AAPL, $MSFT and $GOOGL.

Data comes from public SEC Form 4 and 13F filings and STOCK Act disclosures. Dates are the trade or filing date reported. This page is for research only and is not investment advice.

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