Cryptocurrency giant Coinbase Global Inc. is gearing up for what investors expect to be a blockbuster stock-market debut, though doubts persist about its lofty valuation.

Coinbase plans to go public Wednesday through a direct listing on the Nasdaq Stock Market . The company, which runs the largest U.S. exchange for bitcoin and other digital currencies, could achieve a bigger market capitalization than any of the world’s traditional exchange operators. But it faces a number of threats, including competition in the fast-evolving cryptocurrency industry, that could undermine its stock price in the long run.

Based on the price of Coinbase shares in private-market trading earlier this year, the company is worth $91.5 billion on a fully diluted basis, securities filings show. And Coinbase reached that valuation even before releasing blowout results for the first quarter, when it benefited from a huge rally in the price of bitcoin.

During the first three months of 2021, Coinbase attracted 13 million new users and estimated it generated earnings of $730 million to $800 million on revenue of $1.8 billion. Even at the lower end of that earnings range, that’s more than twice its profit for all of last year.