RE: So you purchased EOS on an exchange ? Why you need to register your Ethereum Wallet address at EOS.IO, prior to the 1 June 2018 ! by eos-helpguide

Viewing a response to: @eos-helpguide/so-you-purchased-eos-on-an-exchange-why-you-need-to-register-your-ethereum-wallet-address-at-eos-io-prior-to-the-1-june-2018

US citizens can not participate in ICO, but I do not think it translates into they can not own EOS tokens from secondary market.