Would taxing foreign investors' US holdings weaken the dollar?
Core argument: Section 899 of the One Big Beautiful Bill Act, before the Senate, would let the Treasury secretary levy a 5% surcharge on the US investments of countries applying "extraterritorial and discriminatory" taxes, rising in stages to 20%.
Three numbers are sending a spasm of concern through Wall Street: 899. That’s the clause of the One Big Beautiful Bill Act currently before the Senate that gives the Treasury secretary the power to levy retaliatory taxes on the US investments of foreign countries that have levied “unfair taxes” on US companies. [The] Treasury must tell Congress each quarter which countries apply “extraterritorial and discriminatory” taxes (the EU’s digital services tax is a prime example), and can then levy a 5% tax surcharge on their investments in the US, which could rise in stages to 20%. This matters because: Capital flows can be stopped far more easily than trade in goods; it gives the US a new weapon for negotiations (or to shoot itself in the foot); once passed by Congress, it has stronger legal grounding than tariffs; It’s really likely to happen; and future Democratic administrations might well leave it in place. Financially, the chief effects would be to weaken the dollar, a key administration aim, and to help foreign markets outperform the US.

