Amid an intense battle with rival Uber, Lyft is reportedly raising a massive amount of funding.
Uber might be the biggest ride-hailing company, but rival Lyft hasn’t given up yet.
The San Francisco-based company is reportedly raising a $500 million funding round at a $4 billion valuation, according to the New York Times. Prior to this new cash infusion, Lyft was valued at $2.5 billion.
In late October, reports surfaced that Uber was in the midst of raising $1 billion in new funding, which would bring its total funds to more than $9 billion, and a valuation of $60 billion to $70 billion.
On Tuesday morning, Lyft co-founder and president John Zimmer estimated that the company’s gross annual revenue will be $1 billion. Lyft net revenue would be less because it shares some of that money with drivers. The company arrived at the gross revenue figure based on its gross bookings for October, which totaled roughly $83 million from 7 million rides.
Lyft’s latest round of funding comes at a time when late-stage investors in private tech companies have started to mark down their value of their shares because of a cooling market. This could affect the company’s ability to fundraise as it continues to delay going public.
Although Lyft and Uber fiercely compete in major U.S. cities like San Francisco and New York, Uber’s rapid global expansion has given it an edge. However, in September, Lyft announced a partnership, both financial and operational, with Didi Kuaidi, the largest ride-hailing company in China. In addition to a $100 million investment in Lyft last spring, the two companies will let their respective customers hail rides through the other’s app, creating an extended network for travelers.
Subscribe to Data Sheet, Fortune’s daily newsletter on the business of technology.
For more on Lyft and Uber’s war, watch this Fortune video: