NEW YORK, United States (AFP) — The head of the first mainstream exchange to allow trading in bitcoin futures on Monday called on critics of the virtual currency to express their scepticism in the market.

“Whether it’s a fraud, whether it’s a bubble, whether it’s legitimate… you will be able to express all of those thoughts in a transparent marketplace,” Cboe chief Ed Tilly told AFP just hours after launching bitcoin futures trading.

His Chicago-based marketplace became the first mainstream exchange in the world to allow trading on the controversial cryptocurrency with sales that kicked off Sunday night, and saw bitcoin continue its surge, blowing past US$18,000, and saw Cboe halt trading twice due to the volatility.

The Cboe launch lends legitimacy to an asset that until now had traded only on alternative digital platforms that are completely unregulated. And the debut is expected to be followed later this month by the rival Chicago Mercantile Exchange.

But several major banks sat out the dramatic first day and refrained from serving as intermediaries to trades, including JPMorgan Chase, Barclays, Morgan Stanley, Societe Generale, Citigroup and Bank of America Merrill Lynch.

The financial heavyweights have kept their distance amid fears that clients could sustain deep losses due to major swings in the value of bitcoin.

The Cboe launch, while largely uneventful, once again showcased the asset’s penchant for volatility as the exchange was forced to suspend trading twice due to major price swings. But Tilly said that means the exchange was operating as intended.

The exchange set a policy requiring such halts due to major price moves, for example, requiring a five-minute suspension due to a 20 per cent move.

“So we hit those barriers on price movements and we did halt according to plans,” Tilly said. “All things operated as they should.”

Near 1915 GMT, bitcoin futures for January delivery were at US$17,920, down from an earlier high of US$18,850, but well above the opening price of US$15,000.

Tilly’s message to large banks that stayed on the sidelines is, “Trust us.”

“Let us work this through,” he said. “You will see the market built in the days, weeks and months to come.”

In time, the large banks will develop the “comfort to open this up to more of their customers who are certainly looking to satisfy the demand for exposure to cryptocurrencies and certainly bitcoins”.