MiNK Therapeutics, Inc. Income Taxes Disclosure

(5) Income Taxes

The Company is subject to taxation in the United States and in various state, local and foreign jurisdictions. The Company remains subject to examination by U.S. Federal, state, local and foreign tax authorities for tax years 2021 through 2024. With few exceptions, the Company is no longer subject to U.S. Federal state, and foreign examinations by tax authorities for the tax year 2021. However, net operating losses from and after the tax year 2017 would be subject to examination if and when used in a future tax return to offset taxable income. The Company’s policy is to recognize income tax related penalties and interest, if any, in its provision for income taxes and, to the extent applicable, in the corresponding income tax assets and liabilities, including any amounts for uncertain tax positions.

As of December 31, 2025, the Company had available net operating loss carryforwards of $71.0 million for Federal and state income tax purposes, which are available to offset future Federal and state taxable income, if any. $70.8 million of these Federal net operating loss carryforwards do not expire, while the remaining net operating loss carryforwards expire in 2037. The Company’s ability to use these net operating losses is limited by change of control provisions under Internal Revenue Code ("IRC") Section 382 and may expire unused. The Company also has foreign net operating loss carryforwards, which do not expire, available to offset future foreign taxable income of $19.1 million generated in the United Kingdom. The potential impacts of these provisions are among the items considered and reflected in the Company’s assessment of its valuation allowance requirements.

Beginning January 1, 2022, the Tax Cuts and Jobs Act (the “Tax Act”) eliminated the option to deduct research and development expenditures in the current year and requires taxpayers to capitalize such expenses pursuant to Internal Revenue Code (“IRC”) Section 174. Under the Tax Act the capitalized expenses are amortized over a 5-year period for domestic expenses and a 15-year period for foreign expenses. On July 4, 2025, the One Big Beautiful Bill Act (“OBBBA”) was enacted in the U.S. The OBBBA contains, among other provisions, changes to the U.S. corporate income tax system, including allowing immediate expensing of U.S. qualifying research and development expenses and allowing taxpayers an election to accelerate the deduction for previously capitalized U.S. research and development costs. The favorable U.S. research and development expenditure provisions increase the net operating loss generated in 2025 but do not have a material impact on the Company’s deferred tax expense as a result of the valuation allowance maintained against the Company’s net deferred tax assets. The Company is electing to continue amortization of the domestic capitalized research and development expenses in 2025. The Company has considered the impact of these provisions, which results in capitalized research expense deferred tax assets of approximately $5.3 and $7.0 million as of December 31, 2025 and 2024 respectively.

In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which the net operating loss and tax credit carryforwards can be utilized or the temporary differences become deductible. The Company considers projected future taxable income and tax planning strategies in making this assessment. To fully realize the deferred tax asset, the Company will need to generate future taxable income sufficient to utilize net operating losses prior to their expiration. Based upon the Company’s history of not generating taxable income, the Company believes that it is more likely than not that deferred tax assets will not be realized through future earnings. Accordingly, a valuation allowance has been established for the full value of the deferred tax assets. The valuation allowance on the deferred tax assets increased by $0.8 million and $1.3 million during the years ended December 31, 2025 and 2024, respectively.

Income tax expense was nil for the years ended December 31, 2025 and December 31, 2024. Income taxes recorded differed from the amounts computed by applying the U.S. Federal income tax rate of 21% to loss before income taxes as a result of the following (in thousands):