Amylyx Pharmaceuticals AMLX Insider Ownership

NASDAQ AMLX

$29.03 +0.26 (+0.90%)

At close: Oct 21, 2026 · 4:00 PM EDT

Insider Holdings by Owner

32.49Mn Shares

Insider Ownership Statistics

as of 30 Sep, 2026

Insider Ownership

8.12%

▲+0.104% pp QoQ

Shares Held by Insiders

9.04Mn

filed for Sep 2026

▲+1.30% QoQ

Shares Outstanding

111.37Mn

111,368,283 shares

Direct Holdings

8.88Mn

Indirect: 166.53K

Net Shares Traded (QoQ)

+115.67K

net buying in Sep 2026

Insiders Holding Shares

with Form 4 holdings on file

Shares Owned by Insiders

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Insiders

Bought Sold

Latest quarter —

Net over range —

Buying quarters —

Insider Ownership Summary

Updated Oct 10, 2026

Over the past 12 months, Amylyx Pharmaceuticals insiders bought $152,183 of stock on the open market (11.9K shares) and sold $10.14 million (574.2K shares).

Behind Amylyx Pharmaceuticals' open-market trades in the past 12 months were one insider buying and 6 insiders selling.
Among Amylyx Pharmaceuticals insiders, Karen Firestone (Director) led open-market buying over the past 12 months with $152,183 of purchases (11.9K shares); the latest was on May 21, 2026.
Conversely, Joshua B. Cohen (Co-Chief Executive Officer) was AMLX's largest open-market seller in the past 12 months, with $3.6 million of sales (221.13K shares); the latest was on September 10, 2026.
George M. Milne Jr. (Director) made the most recent open-market trade by an insider of Amylyx Pharmaceuticals, a sale of 30K shares for $830,904 on October 5, 2026.
Apart from open-market trades, AMLX insiders received 523.64K shares in stock awards, acquired 450K shares through option exercises and conversions and gave away 17.78K shares as gifts in the past 12 months.
Per Business Quant, AMLX insiders together hold 9.01Mn shares based on their latest Form 4 filings, or 8.09% of the 111.37Mn shares outstanding; that total is up 0.96% from 8.93Mn shares at the end of Q2 2026 and up 3.91% from 8.67Mn shares at the end of Q3 2025.
Of the 9.01Mn shares held by Amylyx Pharmaceuticals insiders, 8.85Mn shares (98.15%) are held directly and 166.53K shares (1.85%) indirectly, through trusts, partnerships, family members and other entities.
The insider holdings in Amylyx Pharmaceuticals belong to 10 insiders who have reported on Form 4 within the past two years.
AMLX's largest insider holders by reported holdings are Joshua B. Cohen (Co-Chief Executive Officer, 3.61Mn shares), Justin B. Klee (Co-Chief Executive Officer, 3.61Mn shares) and George M. Milne Jr. (Director, 782.88K shares).
Joshua B. Cohen alone accounts for 40.08% of the shares held by Amylyx Pharmaceuticals insiders.
In the last 12 months, 42 Form 4 filings with transactions in AMLX stock came from 10 insiders.
The insider data for AMLX reflects Form 4 filings through October 7, 2026.

Form 4 Holdings

Insiders Holding AMLX

Insiders 16

Shares held 32.49Mn

Of outstanding 29.18%

#	Insider	Position	Direct	Indirect	Total	Share of Insiders	Last Filed
1	Isaac Cheng	Director	6,578	10,415,650	10,422,228	32.1%	10 Jan, 2022
2	Invest 1 B.V. Als	TenPercentOwner	5,895,280	0	5,895,280	18.1%	08 Jul, 2022
3	Venture Investments Ltd Morningside	TenPercentOwner	4,997,302	0	4,997,302	15.4%	17 Aug, 2023
4	Joshua B Cohen	Co Chief Executive Officer	3,613,123	0	3,613,123	11.1%	14 Sep, 2026
5	Justin B. Klee	Co Chief Executive Officer	3,613,056	0	3,613,056	11.1%	14 Sep, 2026
6	Global Investors Lp Viking	TenPercentOwner	0	1,850,940	1,850,940	5.7%	09 Sep, 2022
7	George M Jr Milne	Director	782,881	0	782,881	2.4%	07 Oct, 2026
8	Camille L Bedrosian	Chief Medical Officer	278,064	0	278,064	0.9%	14 Sep, 2026
9	Margaret Olinger	Chief Commercial Officer	276,108	0	276,108	0.8%	29 Dec, 2023
10	James M Frates	Chief Financial Officer	233,625	0	233,625	0.7%	14 Sep, 2026
11	Patrick D Yeramian	Chief Medical Officer	205,605	0	205,605	0.6%	11 Jan, 2024
12	Gina Mazzariello	Chief Legal Officer	190,838	0	190,838	0.6%	14 Sep, 2026
13	Karen Firestone	Director	116,900	0	116,900	0.4%	02 Sep, 2026
14	Bernhardt G Zeiher	Director	10,000	0	10,000	0.0%	24 Mar, 2025
15	Daphne Quimi	Director	5,000	0	5,000	0.0%	16 May, 2024
16	Paul R. Fonteyne	Director	3,947	0	3,947	0.0%	10 Jan, 2022

Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.

Form 4 Filings

342 Insider Transactions

Source SEC Form 4

Latest quarter Sep 2026

Date	Insider	Position	Transaction	Shares	Price	Value	Shares Held After	Ownership
05 Oct, 2026	George M Jr Milne	Director	Disposed S	30,000	$27.70	$830.90K	782,881	Direct
10 Sep, 2026	Joshua B Cohen	Co Chief Executive Officer	Disposed S	29,545	$32.16	$950.04K	3,614,042	Direct
10 Sep, 2026	James M Frates	Chief Financial Officer	Disposed S	9,768	$32.27	$315.19K	234,667	Direct
10 Sep, 2026	Gina Mazzariello	Chief Legal Officer	Disposed S	9,525	$32.46	$309.14K	190,849	Direct
10 Sep, 2026	Justin B. Klee	Co Chief Executive Officer	Disposed S	29,025	$32.13	$932.55K	3,614,495	Direct
10 Sep, 2026	Camille L Bedrosian	Chief Medical Officer	Disposed S	7,947	$32.21	$256.00K	280,145	Direct
10 Sep, 2026	Camille L Bedrosian	Chief Medical Officer	Disposed S	2,081	$33.09	$68.86K	278,064	Direct
10 Sep, 2026	James M Frates	Chief Financial Officer	Disposed S	1,042	$33.23	$34.63K	233,625	Direct
10 Sep, 2026	Joshua B Cohen	Co Chief Executive Officer	Disposed S	919	$33.15	$30.46K	3,613,123	Direct
10 Sep, 2026	Gina Mazzariello	Chief Legal Officer	Disposed S	11	$33.34	$367	190,838	Direct
10 Sep, 2026	Justin B. Klee	Co Chief Executive Officer	Disposed S	1,439	$33.16	$47.71K	3,613,056	Direct
31 Aug, 2026	Karen Firestone	Director	Acquired M	25,000	$1.76	$44.00K	91,900	Direct
31 Aug, 2026	Karen Firestone	Director	Acquired M	25,000	$5.05	$126.25K	116,900	Direct
31 Aug, 2026	Karen Firestone	Director	Disposed M	25,000	$0.00	$0	0	Direct
31 Aug, 2026	Karen Firestone	Director	Disposed M	25,000	$0.00	$0	0	Direct
18 Aug, 2026	Gina Mazzariello	Chief Legal Officer	Acquired A	21,284	$0.00	$0	200,374	Direct
18 Aug, 2026	Joshua B Cohen	Co Chief Executive Officer	Acquired A	60,039	$0.00	$0	3,643,587	Direct
18 Aug, 2026	Justin B. Klee	Co Chief Executive Officer	Acquired A	60,039	$0.00	$0	3,643,520	Direct
18 Aug, 2026	Camille L Bedrosian	Chief Medical Officer	Acquired A	22,807	$0.00	$0	288,092	Direct
18 Aug, 2026	James M Frates	Chief Financial Officer	Acquired A	22,807	$0.00	$0	244,435	Direct

Showing 1 to 20 of 342 transactions