(Reuters) - Ride-hailing company Lyft Inc beat bigger rival Uber Technologies Inc in filing for an initial public offering (IPO) on Thursday, defying the recent market jitters and taking the lead on a string of billion-dollar-plus tech companies expected to join Wall Street next year.

Lyft’s IPO will test investors’ appetite for the most highly valued Silicon Valley companies and for the ride-hailing business, which has become a wildly popular service but remains unprofitable and has an uncertain future with the advance of self-driving cars.

San Francisco-based Lyft, last valued at about $15 billion in a private fundraising round, did not specify the number of shares it was selling or the price range in a confidential filing with the U.S. Securities and Exchange Commission (SEC).

Lyft could go public as early as the first quarter of 2019, based on how quickly the SEC reviews its filing, people familiar with the matter said. Lyft’s valuation is likely to end up between $20 billion and $30 billion, one source added.

The ride service was set up in 2012 by entrepreneurs John Zimmer and Logan Green and has raised close to $5 billion from investors. While it continues to grow faster than its larger competitor, Uber, it is also losing money.

Lyft would follow a string of high-profile IPOs of technology companies valued at more than $1 billion this year, such as Dropbox Inc and Spotify Technology SA.

However, market turmoil fueled by the escalating trade tensions between the United States and China could dampen enthusiasm for the debuts of other 2019 hopefuls like apartment-rental service Airbnb Inc, analytics firm Palantir Technologies and Stripe Inc, a digital payment company. Including Lyft, these round out four of the top-10 most highly valued, venture-backed tech companies.

An illuminated sign appears in a Lyft ride-hailing car in Los Angeles, California, U.S. September 21, 2017. Picture taken September 21, 2017. REUTERS/Chris Helgren

“Market declines mean that the offer price will be lower than otherwise. But there’s a danger of waiting to go public as well. Markets could go even lower, and the companies could raise less money if they waited longer,” said Jay Ritter, an IPO expert and professor at the University of Florida.

Such fears have pushed some companies to hustle. Uber moved its target IPO date up from the second half of next year to the first half. Some venture capitalists said they are urging portfolio companies that had been planning a public debut in the next 18 months to hurry up and file.

In a key test for the U.S. IPO market on Thursday, Moderna Inc is considering selling up to 20 percent more shares than originally planned in its IPO, allaying concerns that the stock market tumult could derail the biggest flotation of a biotechnology company since 2016, Reuters reported.

FLAG IN THE GROUND

The filing by Lyft, which hired JPMorgan Chase & Co, Credit Suisse and Jefferies as underwriters, plants a flag in the ground to go public before larger rival Uber. The race between them is one of the most closely watched in Silicon Valley.

A provision included in an investment by SoftBank into Uber requires the company to file for an IPO by Sept. 30 or the company risks allowing restrictions on shareholder stock transfers to expire.

Uber investor Mitchell Green, a partner at Lead Edge Capital, said Lyft going public first bodes well for Uber, because if Lyft trades at a high multiple, the much-larger Uber will command even more money.

“Lyft has built a very U.S.-based rideshare business that has done well,” Green said. “If public market investors get excited about that they are really going to get excited about a business that is 5X the size.”

Earlier this year, Lyft said it had 35 percent of the U.S. ride-hailing market. The company operates in the United States and Canada, while Uber is in much of the world and has other businesses including freight-hailing and food delivery.

Both Uber and Lyft have lost huge sums of money by spending heavily competing with each other for passengers and drivers and entering new markets, although they have recently raised prices and reduced subsidies. The companies have held out the promise of boosting profitability by eventually replacing human drivers with robots piloting autonomous vehicles, but a future of cities and suburbs crisscrossed by fleets of self-driving cars is years away, given the technical and regulatory challenges, particularly in the United States.

“With autonomous cars on the horizon, it is anyone’s guess where this sector goes in the future,” said Jeff Zell, senior research analyst and a partner at IPO Boutique in Florida.

Lyft in particular is one of the newest entrants to self-driving and has only a small robo-taxi service in Las Vegas using another company’s technology. Its investors include General Motors Corp, which holds a 9 percent stake in Lyft that it acquired for $500 million in 2016, but GM has wound down its cooperation with Lyft, choosing instead to acquire the autonomous car company Cruise.

Lyft presents other risks, including unresolved questions about its workforce of independent contractor drivers. A decision by the California Supreme Court earlier this year, which makes it easier for workers to prove they are employees and sets a higher standard for companies to treat workers as contractors, threatens to upend Lyft and Uber’s business models. Both companies face legal battles with drivers over their classification.