Signature Bank is facing a class-action lawsuit for its involvement with the now-bankrupt cryptocurrency exchange FTX.

The suit, filed by algorithmic trading firm Statistica Capital and Statistica Ltd., accuses the bank of “substantially facilitating” the FTX fraud by allowing the commingling of FTX customer funds within its proprietary blockchain-based payments network, Signet.

Statistica alleges that it had advised Signature that the funds were meant for FTX, but the bank transferred them to accounts controlled by Alameda Research, the trading firm owned by FTX founder Sam Bankman-Fried.

This revelation of the blurred lines between FTX and Alameda was a major factor in FTX’s collapse. Signature Bank was previously known as one of Wall Street’s most crypto-friendly banks, but the outcome of this lawsuit remains to be seen.

Signature Bank’s shares were down slightly in pre-market trading, and the company did not immediately respond to a request for comment.