WESTFIELD CAPITAL MANAGEMENT CO LP

CIK 0001177719 · Q1 2026

13F Equity AUM

$23.8B

-0.7% QoQ

Positions

250

+9 QoQ

AUM Rank

#365

Top 3%

Skill Alpha (FF)

-0.4%/yr^ns

No Clear Edge

Rank #2,844 · Top 35%

vs S&P -0.4%/yr (unadj.)

Quarters Tracked

~13 years

Portfolio Concentration

Top 5: 19.1%Top 10: 30.3%Top 20: 42.7%

NVDA4.6%

ASND4.6%

FIX3.6%

AAPL3.3%

FTAIN2.9%

MSFT2.6%

GOOGL2.5%

HWM2.2%

VRT2.0%

AMZN2.0%

Others (240)69.7%

HHI (Herfindahl-Hirschman Index) measures portfolio concentration. Low (<1500) = diversified, Moderate (1500-2500), High (>2500) = concentrated bets.

Sector Allocation

Technology28.6%

Industrials23.6%

Healthcare14.9%

Consumer Cyclical10.2%

Financial Services8.4%

Communication Services6.2%

Energy2.6%

Other5.4%

Portfolio weight by GICS sector based on latest 13F filing. Sectors below 2% are grouped as “Other.”

Position Sizing

Positions: 250Median: 0.25%Avg: 0.40%

0–0.5%

198(37.2%)

0.5–1%

34(21.9%)

1–3%

14(24.8%)

3–5%

4(16.2%)

5%+

0(0.0%)

Count of positions per weight bucket — (%) = combined portfolio weight

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Portfolio Overlap

Shared: 250Unique: 0vs 20 funds

3.4%Low

250

Fund positions

7,299

Consensus CUSIPs

Jaccard similarity of this fund’s portfolio vs the consensus of top 20 funds by AUM. Low (<15%) = contrarian, Moderate (15-40%), High (>40%) = follows the crowd.

Most Similar Funds

Top 9 benchmark funds with highest portfolio overlap (Jaccard similarity)

BlackRock, Inc.

6.3%

MORGAN STANLEY

4.7%

BANK OF AMERICA CORP /DE/

5.3%

JPMORGAN CHASE & CO

5.1%

FMR LLC

8.3%

GEODE CAPITAL MANAGEMENT, LLC

STATE STREET CORP

VANGUARD CAPITAL MANAGEMENT LLC

6.9%

VANGUARD PORTFOLIO MANAGEMENT LLC

8.3%

Jaccard similarity per fund: shared CUSIPs / (fund A + fund B − shared). Higher values indicate more similar portfolios.

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Position Changes This Quarter

New46Increased118Decreased77Exited37

New Positions

LNG0.6%

+459K

AS0.5%

+3.9M

AIG0.5%

+1.5M

JLL0.4%

+348K

ROST0.4%

+472K

WWD0.4%

+272K

ANET0.4%

+780K

LTH0.4%

+3.2M

MTZ0.3%

+250K

DWD0.3%

+497K

Increased

CELH0.6%

+2.2M(+144%)

BRZE0.4%

+1.8M(+82%)

PR0.7%

+1.5M(+26%)

ADPT0.3%

+1.4M(+34%)

APG0.8%

+1.2M(+34%)

KEY0.4%

+1.2M(+29%)

IOT0.7%

+1.1M(+28%)

IM8N1.0%

+1.0M(+240%)

RGTI0.1%

+960K(+103%)

DT0.7%

+853K(+25%)

Decreased

GENI0.0%

-5,744,053(-97%)

BAC0.2%

-2,756,724(-72%)

OPCH0.1%

-1,582,491(-57%)

DC40.0%

-1,412,615(-98%)

FITB0.5%

-1,361,504(-36%)

RVMD0.6%

-1,288,435(-45%)

HQY0.3%

-1,239,604(-63%)

3M40.3%

-1,180,820(-78%)

SMTC0.4%

-1,168,018(-48%)

CWST0.3%

-842,734(-51%)

Exited

-1,057,077

-812,215

-6,992,907

-4,118,355

-474,397

-302,307

-2,383,054

-933,553

-547,403

-254,044

Quarter-over-quarter changes compared to prior 13F filing. New = first appearance; Exited = no longer held.

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Holdings

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