Banks have “little or no appetite” to get involved with bitcoin and cryptocurrencies due to fears of a bubble and illicit activity associated with it, the chief executive of Credit Suisse said Thursday.

“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,” Tidjane Thiam said at a news conference, according to Reuters.

The banking executive’s comments came as the digital currency surpassed $7,000 for the first time.

Thiam added that investors were only buying into the digital asset “to make money,” and described it as “the very definition of speculation and the very definition of a bubble.”

The chief financial officer of ING also weighed in on cryptocurrency worries Thursday, saying that, although digital assets are an effective means of exchange, the bank was not advising clients to in invest in them.

“Well, we are quite careful on this part, so if you ask, ‘Are we advising our clients to invest in this?’ the answer is no,” Koos Timmermans told CNBC Thursday.

“We see the superiority of cryptocurrencies in terms of a means of exchange, so that part is fine. But if you then say, ‘Can you easily attach future value to it?’ — and that’s one of the main functions of currency — that is rather difficult because you still don’t know how much the supply of this currency is connected to the demand, we don’t know what the interest rates are.”

But analysts believe that more institutional investors will begin to get involved with cryptocurrencies, after CME Group said it would introduce bitcoin futures contracts.

“Futures from an incumbent exchange bring bitcoin and cryptocurrencies into the regulatory fold,” Charles Hayter, CEO of cryptocurrency comparison website Crypto Compare, told CNBC in an email Thursday.

“This allows more complex financial products to be created and will eventually open the doors to institutional money.”