Celsius filed a lawsuit against Tether, accusing it of improper use of assets and claiming approximately $3.5 billion, including Bitcoin return, damages and legal fees. Celsius claimed that during the bankruptcy proceedings, Tether had loaned it USDT stablecoins and used 39542.42 BTC as collateral. After the price of Bitcoin fell, Celsius was asked to provide more collateral to avoid liquidation. Celsius believes that Tether liquidated BTC without giving it the opportunity to replenish collateral. Tether responded that the lawsuit was unfounded and "extortion", and promised to defend itself vigorously. (Cointelegraph)