WESTFIELD CAPITAL MANAGEMENT CO LP

Position in INSM — INSMED Inc

CIK 1177719 BOSTON, MA

Position in INSM

as of Jun 30, 2026 · filed Aug 12, 2026 Compact

Position Value

$173,743,793

-$66,378,622 QoQ

Shares Held

1,629,561

+11.0% QoQ

Ownership

0.746%

of shares outstanding

% of Portfolio

0.57%

of 13F equity value

Holder Rank

#25

of 665 holders

Holding Since

Jun 2020

13 quarters on record

Voting authority Sole 87% Shared 0% None 13%

Healthcare · as of Jun 30, 2026

WESTFIELD CAPITAL MANAGEMENT CO LP holds $3,083,455,798 across 23 Biotechnology names. INSM ranks #4 (5.6% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	ASND	Ascendis Pharma A/S	4,798,267	$1,279,793,774
2	RYTM	Rhythm Pharmaceuticals, Inc.	2,208,595	$245,220,302
3	ABVX	Abivax S.A.	1,309,825	$174,547,279
4	INSM	INSMED Inc This page	1,629,561	$173,743,793
5	PTCT	Ptc Therapeutics, Inc.	1,956,156	$159,563,644
6	PCVX	Vaxcyte, Inc.	2,472,428	$143,722,239
7	LEGN	Legend Biotech Corp	4,430,063	$127,940,219
8	RVMD	Revolution Medicines, Inc.	600,821	$112,521,756

13 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-06-30	$173,743,793	1,629,561	+11.0%	Shares	Sole	2026-08-12
2026-03-31	$240,122,415	1,468,459	+239.5%	Shares	Sole	2026-05-11
2025-12-31	$75,275,954	432,521	-11.4%	Shares	Sole	2026-02-11
2025-09-30	$70,266,367	487,927	-63.6%	Shares	Sole	2025-11-12
2025-06-30	$134,785,944	1,339,288	-4.8%	Shares	Sole	2025-08-12
2025-03-31	$107,310,200	1,406,609	+49.9%	Shares	Sole	2025-05-09
2024-12-31	$64,797,561	938,551	+272.8%	Shares	Sole	2025-02-11
2024-09-30	$18,376,947	251,739	-74.0%	Shares	Sole	2024-11-12
2021-06-30	$27,523,068	967,079	-5.5%	Shares	Sole	2021-08-10
2021-03-31	$34,850,600	1,023,212	-20.0%	Shares	Sole	2021-05-14
2020-12-31	$42,567,124	1,278,676	-4.0%	Shares	Sole	2021-02-12
2020-09-30	$42,826,164	1,332,488	+28.5%	Shares	Sole	2020-11-13
2020-06-30	$28,551,020	1,036,711	—	Shares	Sole	2020-08-13
No filing history on record for this holder in this stock.