NEW YORK (Reuters) - JPMorgan Chase & Co (>> JP Morgan Chase & Company) Chief Executive Officer Jamie Dimon got the market's attention by calling bitcoin a "fraud" last month, but he declined to discuss the topic on Thursday as his finance chief dialed back some of his earlier comments.

"We are very open minded to the potential use cases in future for digital currencies that are properly controlled and regulated," Chief Financial Officer Marianne Lake said during a call with reporters to discuss the bank's third quarter earnings.

Lake also said the bank is "very optimistic" about some of the technology that underlies bitcoin and other digital currencies, a view echoed by Citigroup Inc (>> Citigroup) CFO John Gerspach on that bank's earnings call with reporters, also on Thursday.

Gerspach said he sees potential for a "real commercial application" for blockchain, the technology that powers trading in digital currencies like bitcoin.

Gerspach also said cryptocurrencies themselves are "worthy of exploration."

The comments came on a day when the price of bitcoin soared above $5,000 for the first time.

The rise of bitcoin and other digital currencies has created a divide on Wall Street.

While many support the use of blockchain, a ledger technology, to speed up and improve trading more broadly, some bankers are opposed to dabbling in actual cryptocurrencies that are not regulated or backed by national governments and have been involved in a number of scandals.

In addition to calling bitcoin a fraud in September, Dimon said he would fire any traders at his bank who touched bitcoin.

Within weeks, CEOs of rivals Morgan Stanley (>> Morgan Stanley) and Goldman Sachs Group Inc (>> Goldman Sachs Group) offered different views, saying the currency was worth further consideration.

On Thursday's call, when asked about the topic again, Dimon laughed and said, "I am not going to talk about bitcoin anymore."

(Reporting by David Henry and Dan Freed; Editing by Lauren Tara LaCapra and Chris Reese)

By David Henry and Dan Freed