Credit Suisse CEO Tidjane Thiam said banks have “little or no appetite” for bitcoin and other cryptocurrencies, citing fears of a potential bubble and the unsavory reputation of it as a way to launder illicit profits.

Thiam was speaking at a conference in Lusanne, Switzerland when he was interviewed by Reuters.

“I think most banks in the current state of regulation have little or no appetite to get involved in a currency which has such anti-money laundering challenges,” Thiam said, according to Reuters. Thiam described cryptocurrency as “the very definition of speculation and the very definition of a bubble.”

Thiam is the latest head of a major bank to cast aspersions against bitcoin. The traditional financial industry has largely cast a cold eye on bitcoin and altcoins, with some speculating that their prejudice stems from a fear that their roles in the world economy could be diminished by decentralized monetary systems.