X0306 4 2022-07-06 1 0001658551 Amylyx Pharmaceuticals, Inc. AMLX 0001920501 ALS Invest 1 B.V. C/O EERSTE WETERINGDWARSSTRAAT 54E AMSTERDAM P7 1017 TP NETHERLANDS 0 0 1 0 Common Stock 2022-07-06 4 S 0 18312 19.54 D 5937577 D Common Stock 2022-07-06 4 S 0 10395 20.60 D 5927182 D Common Stock 2022-07-06 4 S 0 29595 21.32 D 5897587 D Common Stock 2022-07-06 4 S 0 2307 22.42 D 5895280 D The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $19.00 to $19.975, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (1), (3), (4) and (5) to this Form 4. The Reporting Person is managed by SUNU Ventures BV. Felix-Andre von Coerper is the sole corporate director of SUNU Ventures BV and has voting and dispositive power with respect to the securities held by the Reporting Person. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $20.00 to $20.99, inclusive. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $21.00 to $21.73, inclusive. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $22.03 to $22.655, inclusive. /s/ Felix-Andre von Coerper 2022-07-08