Two of Europe’s biggest banks may have lost as much as $300 million in the alleged K1 Group hedge fund fraud.

According the arrest warrant for K1 founder Helmut Kiener, Barclays may have lost as much as $240 million and BNP Paribas $60 million. At least two other banks, JPMorgan Chase and Société Générale, may have been duped by Kiener, with total losses of about $400 million.

Bloomberg News reports that Barclays’ money is “for the most part gone.” According to German prosecutors, Kiener may have misappropriated some $220 million from Barclays, using the money contrary to agreements with K1’s hedge funds. Another deal with Barclays earned Kiener some $20 million in management fees.

For its part, BNP’s potential losses stem from an investment with K1. Prosecutors say Kiener may have deceived the French bank, as well.

Kiener was arrested Wednesday on suspicion of fraud and breach of trust. Two others were arrested in the U.S. as part of his alleged scam.