According to Fortune, Lyft raised $600 million in Series I funding at a $15.1 billion post-money, doubling the ride-hailing company's valuation in little over a year. Fidelity led the round, and was joined by investors including Senator Investment Group. This capital infusion makes Fidelity one of Lyft's largest investors with more than $800 million invested.

Here are some additional notes:

-In total, Lyft has raised $5.1 billion in funding. Lyft's investors include AllianceBernstein, Baillie Gifford, and KKR & Co.

-Rival Uber has raised more than $21 billion to date from investors including SoftBank, TPG, Tencent, and Goldman Sachs.

-Lyft's valuation went from $7.5 billion in April 2017 (Series G funding) to $15.1 billion in June 2018 (Series I).

-To compare, Uber said it would hold a secondary stock sale for employees and existing investors that would value the company at $62 billion, up from the $48 billion valuation it commanded in a secondary sale late last year.

-Lyft claims it has 35% market share in the U.S. (17% in January 2016, 22% in January 2017), although Uber remains the market leader.

-Lyft has a bookings run rate based on Q2 estimate of $7.7 billion.

The news is significant because Lyft made major strides at the expense of its main competitor, Uber. The massive injection of capital makes sense as Uber has Softbank behind it. In the ride-hailing wars, money matters. As Uber CEO Dara Khosrowshahi said about accepting an investment from SoftBank, "Rather than having their capital cannon facing me, I'd rather have their capital cannon behind me."

Lyft has spent the last year and a half aggressively expanding into new U.S. markets, entering Canada, and investing in autonomous vehicle projects. Oh, and it's reportedly nearing a deal to buy bike-share company Motivate for at least $250 million. That all requires a lot of $$$.

The new fundraise also likely means that Lyft is not planning to go public in the near future.