An unauthorized message posted to the US Securities and Exchange Commission's official X account briefly sent bitcoin prices soaring, forcing the market regulator to deny it had approved a new cryptocurrency product.

Just after 4 pm local time (2100 GMT), the price of the world's largest digital currency in terms of circulation surged towards its highest level for more than 22 months, before falling again a few minutes later.

The jump in the price of bitcoin to almost $48,000 came immediately after the SEC published a message on its X account (formerly Twitter) suggesting that it had approved the long-awaited launch of a new type of investment product, known as an ETF.

But minutes later, SEC Chairman Gary Gensler took to his own X account to warn that the market regulator's account had been "compromised" and that an "unauthorized tweet" had been posted there.

"The unauthorized tweet regarding bitcoin ETFs was not made by the SEC or its staff," an SEC spokesperson later told AFP.

The market has been speculating for weeks that the SEC would grant approval for this new product, which would, for the first time, offer investors an index fund that replicates the performance of bitcoin without them having to hold the cryptocurrency directly.

Last year, a federal appeals court in Washington confirmed that the SEC was not justified in its decision to deny asset manager Grayscale approval for its bitcoin ETF, sparking speculation that it would soon approve such a fund.

The Wall Street regulator has until Wednesday to rule on the oldest application for a bitcoin ETF currently under consideration, that of the investment company 21Shares.

If the SEC were to give the ETF the green light, analysts widely expect it would broaden the appeal of -- and access to -- bitcoin and accelerate the adoption of this digital currency.