Company: SION
Filing Date: 2025-02-03
Form Type: S-1/A
Source: 0001193125-25-018825
Chunk: 304

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-03
Form: S-1/A
Chunk 304
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 the payment of the dividends and must be updated periodically. If the non-U.S.holder holds our common stock through a financial institution or other agent acting on the non-U.S.holder’s behalf, the non-U.S.holder will be required to provide appropriate documentation to the agent, which then will be required to provide certification to us or our withholding agent, either directly or through other intermediaries. 216

Non-U.S.holders that do not provide the required certification on a timely basis, but that qualify for a reduced treaty rate, may obtain a refund or credit of any excess amounts withheld by timely filing an appropriate claim with the IRS. Non-U.S.holders should consult their tax advisors regarding any applicable income tax treaties that may provide for different rules. If a non-U.S.holder holds our common stock in connection with the conduct of a trade or business in the U.S., and dividends paid on our common stock are effectively connected with such holder’s U.S. trade or business (and are attributable to such holder’s permanent establishment or fixed base in the U.S. if required by an applicable tax treaty), the non-U.S.holder generally will be exempt from U.S. federal withholding tax. To claim the exemption, the non-U.S.holder must generally furnish a valid IRS Form W-8ECI(or applicable successor form) to the applicable withholding agent. However, any such effectively connected dividends paid on our common stock generally will be subject to U.S. federal income tax on a net income basis at the regular U.S. federal income tax rates in the same manner as if such holder were a resident of the U.S. A non-U.S.holder that is a foreign corporation also may be subject to an additional branch profits tax equal to 30% (or such lower rate specified by an applicable income tax treaty) of its effectively connected dividends, as adjusted for certain items. Amounts not treated as dividends for U.S. federal income tax purposes will constitute a return of capital and will first be applied against and reduce a holder’s tax basis in our common stock, but not below zero. Any excess will be treated as gain realized on the sale or other disposition of our common stock and will be treated as described under “ —Gain on Sale or Other Taxable Disposition of Our Common Stock” below. Gain on Sale or Other Taxable Disposition of Our Common Stock Subject to the discussion below regarding backup withholding and FATCA (as defined below), a non-U.S.holder generally will not be subject to U.S.