Shattuck Labs, Inc.

On February 2, 2026, Arunthathy Nirmalini (Lini) Pandite, M.B.Ch.B., the Company's Chief Medical Officer, adopted a trading plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act (a “10b5-1 Plan”). Dr. Pandite’s 10b5-1 Plan provides for the potential sale of up to 83,514 shares of the Company’s common stock and will expire on the earlier of June 30, 2027 or the date when all shares under Dr. Pandite’s 10b5-1 Plan are sold.

On February 2, 2026, Abhinav Shukla, PhD., the Company's Chief Technical Officer, adopted a trading plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. Dr. Shukla’s 10b5-1 Plan provides for the potential exercise of stock options to purchase up to 168,659 shares of the Company's common stock and subsequent sale of a portion of the exercised options to cover the exercise price and estimated income taxes associated with the exercise. The 10b5-1 Plan will expire on the earlier of January 29, 2027 or the date when all shares under Dr. Shuckla’s 10b5-1 Plan are exercised.

The adoption of Dr. Pandite and Dr. Shukla's 10b5-1 plans were in accordance with both the Company's insider trading policy and SEC rules and regulations, on the date of adoption.

Other than as described above, during the three months ended March 31, 2026, none of our directors or Section 16 officers (as defined in Rule 16a-1(f) under the Exchange Act)adopted orterminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K.