Uber’s potential value in a public offering and Lyft’s underwriter were first reported by The Wall Street Journal on Tuesday.

Uber’s I.P.O. is likely to be among the biggest financial events on Wall Street next year. At $120 billion, it would rival the total value of Facebook when it went public in 2012 with a market capitalization of $104 billion, Ms. Smith said.

Unlike Facebook in 2012, Uber is not profitable on a day-to-day basis. Uber has been trying to shed its most money-losing businesses since Dara Khosrowshahi became its chief executive last year and has pulled back from expensive expansion plans in Russia, China and Southeast Asia.

The company did turn a profit in the first quarter of 2018 thanks to the sale of some of those operations, but the second quarter was a return to form. Uber reported a $891 million loss, even though its bookings — the amount of money taken in by drivers — were up 41 percent from a year earlier and its revenue hit $2.7 billion.

As a privately held company, Uber is not required to publicly disclose its quarterly results. But for some time it has revealed basic financial information to give investors a better sense of its health.

The $120 billion valuation would also be a huge jump from earlier estimates. In December, the Japanese conglomerate SoftBank and a consortium of investors announced plans to buy 17.5 percent of Uber at a price of about $33 a share. That put Uber’s value at about $48 billion.

At the time, Uber was struggling to overcome a range of management issues, and the SoftBank investment was a steep discount from earlier rounds, which priced the company as high as $70 billion.