Lyft Inc. today announced that it has secured a $600 million round of funding from Fidelity Investments Inc., the world’s fourth-largest asset manager, and hedge fund Senator Investment Group LP.

The investment values the ride-hailing company at a massive $15.1 billion. It comes just six months after Lyft received a $500 million cash infusion that also saw the participation of Fidelity, which led today’s round. 

Investors’ confidence in Lyft has enabled the company to pursue an aggressive expansion strategy. Lyft announced in May that its share of the U.S. ride hailing market had surpassed 35 percent, up from 20 percent just 18 months prior. The startup claimed at the time that this figure was above 50 percent in “multiple” regions.

A good portion of Lyft’s recent gains has likely come at the expense of Uber Technologies Inc., its chief rival and the dominant player in the ride-hailing industry. But the latter company still maintains a comfortable lead, as reflected by the fact that it was valued at $48 billion late last year. A planned secondary stock sale that Uber announced in May is expected to hike its valuation to $62 billion.

The end game is an initial public offering. Last month, Uber Chief Executive Dara Khosrowshahi said that the ride-hailing giant is on track to hit the stock market in 2019, reaffirming a commitment he made two years prior. 

The New York Times reported last October that Lyft had been exploring an IPO as well. According to the paper’s sources, the company held talks with investment banks about going public in 2018. That’s probably off the table in light of Lyft’s new $600 million haul, but an IPO might not too far away either if Uber’s roadmap is any indication.

Lyft has raised more than $4.3 billion in funding to date.

Image: Lyft