Today CNG sent out a letter describing how tariffs will affect purchases. Here's an excerpt. It's pertinent to ALL offshore coin purchases, and not just ancients. Bullion purchases from offshore sellers will become prohibitively expensive.
No coins have been exempted from the tariffs.
Coins entering the United States will be subject to tariffs based on the country of origin, meaning the country of manufacture. A coin from a mint located in what is now modern Greece will be tariffed at the rate for Greece (i.e., the European Union) regardless of where the coin has been held or where it is shipped from.
Although tariffs are not the same as import VAT, our European customers and colleagues are familiar with the taxation of incoming coins. US customers have not had to deal with this issue in the past. One difference from import VAT is that, as far as we know, tariffs that are paid cannot be reclaimed later upon export from the US.
Coins already in the United States and sold to buyers in the United States are not subject to any tariff.
Coins already in the United States and sold to buyers outside the United States continue be subject to regulations of the buyer's home country.
Coins purchased by US buyers from dealers or auction houses abroad will be subject to US tariffs, even if those coins were consigned to the sellers by collectors or dealers in the US.
CNG adds that all of the coins in their auctions through June are already in the US.