Online accommodation marketplace Airbnb Inc. has raised $1 billion in a late-stage round that is believed to have included Google Capital and TCV.

First reported by CNBC, the Series F round consisted of two parts, an initial $555 million raised and reported by a Securities and Exchange Commission filing lodged in September and an additional $445 million declared by a new SEC filing today. The valuation on the round was $31 billion, up from the $30 billion valuation used for its last $850 million round in mid-2016.

Airbnb is believed to have become profitable in the second half of 2016 and continues to remain profitable in 2017, according to sources quoted by VentureBeat, in line with the company’s previously stated ambitions to become profitable in 2016. It has also said it’s aiming for revenues of $10 billion by 2020.

Since being founded in 2008, Airbnb has grown into a giant in the accommodation industry, matching homeowners with spare rooms or vacant accommodations with those looking to rent primarily over short periods of time. It has approximately 3 million homes, apartments and rooms for rent in 65,000 cities in 191 countries, a figure that is more than the top three hotel chains combined.

The company has used some of the money it has raised to expand its business, acquiring high-end vacation rental service Luxury Retreats in a deal believed to be worth $300 million last month, along with social payments startup Tilt the same month.

Other than growing its business, it’s not clear why Airbnb has raised yet another round. Some new speculation suggests that it may be part of an ongoing effort by the company to delay having to go down the initial public offering path. That idea is also supported by a report that Airbnb’s last round included a $200 million stock buyback from employees, a move often undertaken by late-stage startups looking to remain private while offering some liquidity options to early employees and investors.

Including the new round, Airbnb has raised around $4 billion to date. Previous investors include SherpaCapital, TPG Growth, T. Rowe Price, Dragoneer Investment Group, Founders Fund, CrunchFund, Sequoia Capital, Ashton Kutcher and Andreessen Horowitz.

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