Lyft is now worth $15.1 billion -- twice what it was worth just last year.

On Wednesday, the ride-sharing company said it raised another $600 million, capping its remarkable run since April 2017, when it was valued at $7.5 billion. Fidelity Investments -- one of the startup's biggest backers -- led the latest funding round, which was first reported by the Wall Street Journal. The asset manager has poured more than $800 million into Lyft.

Previous investors include the CapitalG unit of Google's parent company Alphabet (GOOGL), private equity firm KKR and Japanese e-commerce giant Rakuten. Those firms did not participate in the most recent funding round.

Related: Lyft makes its trips carbon neutral in bid to fight climate change

Ride-sharing rival Uber remains the dominant player, with a valuation pegged at $62 billion in a recent secondary stock sale. But Lyft has seen its market share increase as Uber battled a variety of controveries over the last year. Among its biggest challenges were allegations of a toxic corporate culture and accusations that at least 103 Uber drivers in the US have sexually assaulted or abused passengers since 2014 (CNN also found 18 cases of Lyft drivers accused in the past four years).

More recently, one of Uber's self-driving cars struck a pedestrian in Tempe, Arizona, a major setback to the company's autonomous driving operations. Uber announced plans to stop robo-car tests in Arizona and lay off 300 employees.

Lyft now holds 35% of the ride-sharing market in the US, up from 22% in January 2017 and 17% in January 2016.

Although it remains unclear whether Lyft plans to go public anytime soon, Uber CEO Dara Khosrowshahi said last year his hopes to file to file an IPO next year.