Lyft has raised $600 million in additional funding, valuing the ride-hailing company at $15.1 billion. The money will fund the company’s heated competition with the much more valuable — and better funded — Uber.

The funding round was led by Fidelity Management and Research Company, and was raised primarily from existing investors. It comes over six months after raising $1.5 billion led by CapitalG, Google’s venture arm. At the time, the company was valued at $11.5 billion.

The financing news comes at a time when its main rival Uber is beginning to stabilize after a bruising 2017. Lyft had sought to capitalize on the #DeleteUber phenomenon by marketing itself as a more “woke” alternative. Lyft gained market share and spread into Canada, while Uber confronted obstacles in its overseas markets.

Lyft had sought to capitalize on the #DeleteUber phenomenon

This year Lyft is on a pace to record $7.7 billion in gross bookings, the amount it takes in before paying out drivers, according to The Wall Street Journal. Uber, by comparison, had $37 billion in gross bookings last year. Earlier this year, Uber raised $1.25 billion from Japanese tech giant SoftBank, and is reportedly eyeing an IPO in the latter half of 2019.

Both companies are also racing to develop self-driving car technology, even though Uber is still reeling from a fatal crash in Arizona involving one of its autonomous vehicles this past March.

The result of the rivalry has been a boon for riders: low fares, easier-to-use apps, and bigger bonuses for drivers — which translates to bigger cash burns for both companies, neither of which has managed to turn a profit.