WESTFIELD CAPITAL MANAGEMENT CO LP

Position in XENE — Xenon Pharmaceuticals Inc.

CIK 1177719 BOSTON, MA

Position in XENE

as of Mar 31, 2026 · filed May 11, 2026 Compact

Position Value

$81,496,236

+$26,512,360 QoQ

Shares Held

1,401,483

+14.2% QoQ

Ownership

1.45%

of shares outstanding

% of Portfolio

0.34%

of 13F equity value

Holder Rank

—

not a current holder

Holding Since

Dec 2023

10 quarters on record

Voting authority Sole 92.4751852145192.ToString("F0")% Shared 0.ToString("F0")% None 7.5248147854808085.ToString("F0")%

Healthcare · as of Mar 31, 2026

WESTFIELD CAPITAL MANAGEMENT CO LP holds $2,468,245,086 across 19 Biotechnology names. XENE ranks #8 (3.3% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	ASND	Ascendis Pharma A/S	4,813,440	$1,100,978,131
2	INSM	INSMED Inc	1,468,459	$240,122,415
3	PCVX	Vaxcyte, Inc.	3,646,138	$211,877,079
4	RYTM	Rhythm Pharmaceuticals, Inc.	1,929,123	$167,775,827
5	RVMD	Revolution Medicines, Inc.	1,556,578	$151,377,210
6	ABVX	Abivax S.A.	1,322,938	$147,309,146
7	LEGN	Legend Biotech Corp	5,763,475	$104,261,262
8	XENE	Xenon Pharmaceuticals Inc. This page	1,401,483	$81,496,236

10 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-03-31	$81,496,236	1,401,483	+14.2%	Shares	Sole	2026-05-11
2025-12-31	$54,983,876	1,226,771	+1.7%	Shares	Sole	2026-02-11
2025-09-30	$48,423,549	1,206,066	+4.6%	Shares	Sole	2025-11-12
2025-06-30	$36,076,536	1,152,605	-17.2%	Shares	Sole	2025-08-12
2025-03-31	$46,680,463	1,391,370	+20.2%	Shares	Sole	2025-05-09
2024-12-31	$45,361,808	1,157,189	+72.8%	Shares	Sole	2025-02-11
2024-09-30	$26,362,152	669,600	+4.0%	Shares	Sole	2024-11-12
2024-06-30	$25,091,858	643,546	+85.3%	Shares	Sole	2024-08-14
2024-03-31	$14,953,460	347,351	+46.3%	Shares	Sole	2024-05-10
2023-12-31	$10,939,019	237,495	—	Shares	Sole	2024-02-09
No filing history on record for this holder in this stock.