Amylyx Pharmaceuticals, Inc.

(c)

During the three months ended June 30, 2026, no officers or directors of the Company (as defined in Rule 16a-1(f) under the Exchange Act)adopted, modified orterminated a “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(c) of Regulation S-K of the Exchange Act, except as described below:

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Gina M. Mazzariello, our Chief Legal Officer and General Counsel, adopted a new Rule 10b5-1 trading plan on April 9, 2026, which is scheduled to expire on December 31, 2026. The aggregate number of shares of our common stock authorized to be sold under this new arrangement is 55,000;

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James Frates, our Chief Financial Officer, adopted a new Rule 10b5-1 trading plan on April 10, 2026, which is scheduled to expire on January 31, 2027. The aggregate number of shares of our common stock authorized to be sold under this new arrangement is 40,000;

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George Milne, a member of ourboard of directors, adopted a new Rule 10b5-1 trading plan on April 28, 2026, which is scheduled to expire on December 31, 2026. The aggregate number of shares of our common stock authorized to be sold under this new arrangement is 100,000;

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Joshua Cohen, our Co-Chief Executive Officer and a member of our board of directors, adopted a new Rule 10b5-1 trading arrangement on May 11, 2026, which is scheduled to expire on December 31, 2026. The aggregate number of shares of our common stock authorized to be sold under this new arrangement is 100,000; and

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Justin Klee, our Co-Chief Executive Officer and a member of our board of directors, adopted a new Rule 10b5-1 trading arrangement on May 11, 2026, which is scheduled to expire on December 31, 2026. The aggregate number of shares of our common stock authorized to be sold under this new arrangement is 100,000.