EXAGEN INC.

Rule 10b5-1 trading arrangements

During the three months ended June 30, 2026, none of our directors or officers adopted, modified orterminated a "Rule 10b5-1 trading arrangement" or "non-Rule 10b5-1 trading arrangement," as each term is defined in Item 408 of Regulation S-K.

Lease Agreement

On July 6, 2026, we entered into a new lease with LOA 26 LP for approximately 28,000 square feet of office space located at 2175 Salk Avenue, Carlsbad, CA (the “Lease Agreement”). The commencement date of the lease is May 1, 2027 (the “Term Commencement Date”), and the lease will expire 39 full calendar months after the Term Commencement Date in July 2030 (the “Initial Term”), unless terminated earlier in accordance with the Lease Agreement. Pursuant to the Lease Agreement, the annual rent will be approximately $0.6 million with annual increases of 3% during the Initial Term. We will also be responsible for the payment of additional rent to cover our proportionate share of the annual operating and tax expenses for the building. We have the option to extend the term for one additional three-year period, which is exercisable by written notice delivered not less than 9 months and not more than 12 months prior to the expiration of the Initial Term. The foregoing description of the Lease Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Lease Agreement, a copy of which is filed as Exhibit 10.1 to this Quarterly Report on Form 10-Q.