Around-the-clock trading, a feature of cryptocurrency markets, is likely coming to U.S. equities within five years, some retail brokerages and exchange operators, including Robinhood Markets and Cboe Global Markets, said Thursday.

At Robinhood, nearly three-quarters of the firm's around 14 million active monthly users, whose top recurring investment is in bitcoin, do their investment research outside market hours, and they want to trade at their convenience, said Chief Brokerage Officer Steve Quirk.

"There are a lot of people who work odd hours now in the gig economy and the notion that they have to sit and figure out when they can trade or invest is kind of foreign to them," he said at the Security Traders Association's annual conference in Washington.

He predicted that five years from now 24/7 equities trading will be commonplace, a view widely shared by speakers at the conference.

"I don't even think it will be five years until customers will be able to represent their opinions around the clock," Ed Tilly, chief executive officer of Cboe, said on another panel.

The exchange operator already operates in markets around the globe and has seen interest grow for around-the-clock trading as it has extended the trading hours of its proprietary products tied to the S&P 500 and VIX volatility index, he said.

Retail brokerage Webull also operates globally and is working on 24/7 trading capabilities to satisfy its clients' demands, said CEO Anthony Denier.

Chicago-based market-maker Simplex Trading also anticipates a shift to 24/7 trading and is weighing the logistical challenges, said CEO Erik Swanson.

"It's very nerve racking for me to think about how we're going to do it, whether it's going to be on a lot of Red Bull or whether it's going to be with a follow the sun set up," he said.