The proposed sale of FTX’s non-U.S. business to Binance, announced Tuesday amid concerns over stability at FTX, has drawn concerns of antitrust retaliation in the U.S. and elsewhere.

Regulators across the world have the power to block major mergers if they fear they would limit market choice, and also have strict laws against anti-competitive behavior. Binance is the world’s largest crypto exchange by volume, while FTX is within the top five, according to data site CoinGecko.

Binance Chief Executive Changpeng “CZ” Zhao and FTX boss Sam Bankman-Fried tweeted news of the plans on Tuesday, drawing immediate questions over compliance with antitrust laws.