The estate of collapsed crypto exchange FTX has filed a suit against Binance and its former CEO Changpeng Zhao in an effort to wrest back at least $1.76 billion, citing a “fraudulent” share deal.

In a Sunday filing with a Delaware court, FTX cites a 2021 transaction in which Binance, Zhao and others exited their investment in FTX, selling a 20% stake in the platform and a 18.4% stake in its U.S.-based entity West Realm Shires back to the company.

The FTX estate alleges that the share repurchase was funded by FTX’s Alameda Research division through a combination of the company’s and Binance’s exchange tokens, as well as Binance’s dollar-pegged stablecoin.