Mike Nudelman/Business Insider
The news was reported earlier by the Wall Street Journal.
It's more than the rumored $1 billion round that had leaked two weeks ago, which would have put the company at a $24 billion valuation. It's a still a number higher than hotel chain Marriott ($21 billion) and double the valuation of travel site expedia.
General Atlantic Inc., Chinese firm Hillhouse Capital Group and Tiger Global Management lead the round, according to the source.
The home rental company last raised money in April 2014 at a $10 billion valuation. This round makes it the second highest-valued startup out there today, ranking only behind Uber.