The estate of defunct crypto exchange FTX filed a suit against Binance and its former CEO ChangPeng Zhao seeking to recoup almost $1.8 billion FTX alleges was “fraudulently” transferred to Binance and executives by Sam Bankman-Fried as part of a share deal.

In a filing with a Delaware court on Sunday, FTX alleges that Binance, Zhao and other executives received the funds as part of a share repurchase deal— where a company repurchases their own stocks— in July 2021. The suit asserts that Bankman-Fried facilitated the transaction, allowing Binance to sell their 20% stake in the platform and 18.4% stake in its U.S.-based entity back to FTX.

The share repurchase was funded by Alameda Research, FTX’s sister firm, using a combination of FTX’s native token FTT, Binance’s BNB coins and Binance’s dollar-pegged stablecoin, according to the filing.

The suit alleges that the deal was a “constructive fraudulent transfer,” because FTX and Alameda “may have been insolvent from inception and certainly were balance-sheet insolvent by early 2021,” meaning the firm did not have the funds to afford the transaction.

Binance denied the allegations in an emailed statement shared with Fortune saying, “The claims are meritless, and we will vigorously defend ourselves.”

The estate also cites tweets made by Zhao that it alleges led to the collapse of FTX saying they were “false, misleading, and fraudulent” and “maliciously calculated to destroy his rival…” according to the filing.

In a post on Nov. 6, 2022, Zhao tweeted that Binance would liquidate its FTT tokens, worth over $500 million at the time, causing a market panic where customers rushed to withdraw their funds from FTX.

The lawsuit is just one of many filed by the FTX estate as part of an effort to claw back assets in bankruptcy court. Other suits have targeted the crypto exchange Crypto.com and former White House communications officer and crypto hedge fund operator, Anthony Scaramucci.

Following a flood of customer withdrawals, FTX filed for bankruptcy in late 2022, triggering a flurry of civil and criminal investigations. Almost exactly a year later, Bankman-Fried was sentenced to 25 years in prison in what U.S. attorney Damian Williams called “one of the biggest financial frauds in American history.”