Material Agreement, Corporate Action (Form 8-K)

On March 13, 2026, Seer, Inc. (the "Company") entered into Amendment No. 1 to Tax Benefit Preservation Plan (the "Amendment"), which amends the Tax Benefit Preservation Plan, dated as of February 26, 2026 (the "Plan"), between the Company and Computershare Trust Company, N.A., as rights agent.

The Amendment clarifies the definition of "Beneficial Ownership" and its interaction with Treasury Regulation § 1.382-3(a)(1).

On March 3, 2026, a purported stockholder of the Company filed an amended complaint in the Delaware Court of Chancery against the Company and the members of the Board of Directors in the action captioned Taylorv. Farokhzad, C.A. No. 2025-1232- PAF (such action, the "Delaware Action"). The amended complaint challenged certain aspects of the definition of "Beneficial Ownership" in the Plan and asserted that the Plan's definition of "Beneficial Ownership" could be triggered by an agreement, arrangement, or understanding that would not be considered a change in "economic ownership" under Section 382 of the Internal Revenue Code. The Company believes that the allegations in the Amended Complaint are without merit. Solely to avoid the cost of litigation, the Company agreed to amend the Plan to moot the allegations in the Delaware Action. In connection with dismissal of the Delaware Action as moot, the Company has agreed to pay plaintiff's counsel a mootness fee of $250,000. This payment would fully satisfy any claims by plaintiff or plaintiff's counsel for attorneys' fees, costs, and expenses associated with the Delaware Action.

The foregoing description of the Amendment does not purport to be complete and is qualified in its entirety by reference to the Amendment, a copy of which is attached as Exhibit 4.1 and is incorporated herein by reference.

The information included in Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 3.03.