The US Treasury Department recently froze $344 million held by Iran’s central bank, in two digital wallets that contained Tether (USDT) Stablecoins.

Tether cooperated with Treasury in these actions, intended to shut off Iranian sales of oil.

Stablecoins were promoted as alternatives to traditional banks, and are in wide use outside the United States.

Tether is the largest stablecoin, with transaction volumes higher than Visa and MasterCard, and assets of hundreds of billions of dollars in US Treasury bonds, gold, and other investments.

Stablecoins were also perceived as decentralized, and outside the reach of regulators and governments, except in cases of egregious criminal violations.

Crypto market players reacted violently to the news of the freeze, and (truly decentralized) Bitcoin has traded sharply higher since.