Airbnb just got a big cash infusion — and Google is one of its big investors.

According to a new financial filing, the company has raised $555 million at a $30 billion valuation, part of a desired $850 million round that it filed to raise last month.

Google Capital and Technology Crossover Ventures led the deal, Business Insider has confirmed, after an earlier The Wall Street Journal report.

A person close to the company confirmed that Airbnb plans to file a Form D with the Securities and Exchange Commission on Thursday with details of the raise, and that the round has not closed yet. Airbnb still plans to raise the total $850 million, the person said.

Google Capital is part of Alphabet, Google's parent holding company. It invests in late-stage startups primarily for financial gains, but puts an emphasis on brokering connections with Google. It's led by David Lawee, who used to run mergers and acquisitions for the search giant. It's different from GV (formerly known as Google Ventures), which invests in early-stage startups and functions more like a traditional VC.

The Journal also reported that Airbnb employees were able to sell some of their shares as part of the deal.

That's important for employee retention: As companies like Airbnb stay private for longer than venture-funded tech companies in past eras, employees have fewer options to turn their stock options into usable cash. Deals like this provide much-needed liquidity for those employees.

The company's current valuation makes it the second most valuable US startup behind Uber, which investors have valued at around $68 billion.

The home-sharing company has been experimenting with new business areas. Last month, it launched a "community center" in Japan that functions like a hotel — it will allow tourists to rent rooms — and it's experimenting with ways to provide more guidance to customers when they're planning trips; for instance, a feature called Experiences would pay locals to conduct tours of particular sights.

Airbnb is also facing legal fights, which could get expensive.

In New York, the state Senate passed a bill that would prevent people from advertising short-term rentals, which would basically make it impossible for Airbnb to operate in the state if the governor signs it into law, and the company's home city of San Francisco passed legislation holding Airbnb responsible for enforcing laws related to short-term rentals.