SAN FRANCISCO — Uber is in talks to sell a stake in its self-driving technologies unit to SoftBank and other investors for as much as $1 billion, as the ride-hailing company prepares to go public, according to four people with knowledge of the matter.

The talks are still underway and may not result in an investment, said the people, who asked for anonymity because they were not authorized to speak publicly. Apart from SoftBank, the investor consortium includes an automaker, they added.

Under the terms of the proposed deal, investors would purchase from a pool of Uber stock specifically earmarked for the self-driving technologies unit. Uber would maintain majority control of the self-driving arm and would use the investment to fund its research and development. The deal would value the self-driving business at $5 billion to $10 billion, the people said.

Uber filed confidentially to go public in December in what would be one of the largest tech initial public offerings of recent years. The company, based in San Francisco, could hit a valuation of $120 billion when it reaches the stock market.