Every cross-border tax question eventually collapses into the same underlying issue: is this dollar of income U.S.-source or foreign-source? It sounds like a formality, but the answer drives some of the most consequential numbers on an international return — the foreign tax credit limitation under IRC §904, whether a nonresident alien owes U.S. tax at all under §871 or §882, which income falls into which FTC “basket,” and how a tax treaty's sourcing tie-breakers apply.

If you're holding Bitcoin, Ethereum, or other digital assets on an exchange based outside the U.S. — Binance, a Hong Kong or Singapore-based platform, or an exchange tied to your home country — you may be sitting on a reporting obligation you haven't thought about. Crypto feels borderless, but the IRS and FinCEN don't see it that way. Where your exchange is legally domiciled matters, and getting it wrong can mean penalties that have nothing to do with whether you owed any tax