Sana Biotechnology, Inc.

The Company’s income tax provision for interim periods is determined using an estimate of the Company’s annual effective tax rate, adjusted for discrete items arising in the quarter. The Company’s effective tax rate differs from the U.S. statutory tax rate primarily due to a valuation allowance on the deferred tax assets. Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets.

The Company applies judgment in its determination of the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. As of September 30, 2026 and December 31, 2025, the Company’s uncertain tax positions were immaterial.

The One Big Beautiful Bill Act (OBBBA), enacted on July 4, 2025, introduced notable changes to the U.S. Internal Revenue Code, including immediate expensing of domestic research and development costs that are incident to the development or improvement of a product, process, formula, invention, computer software, or technique. As previously required under the Tax Cuts and Jobs Act, the Company capitalized research and development expenditures in the years ended December 31, 2022 through December 31, 2024. With the enactment of OBBBA, the Company began deducting domestic research and development costs in 2025.