SoftBank Group Corp. invested $300 million in WeWork Cos., a person familiar with the matter said, an influx of cash that values the New York-based co-working giant at more than $17 billion.

The investment from SoftBank is the first in what will probably be a much larger stake, said the person, who asked not to be identified. The additional cash is expected to come from the $100 billion Vision Fund. With the new money, WeWork's valuation increases to about $18 billion, according to an estimate by private stock market provider Equidate.

WeWork, which rents out desks and offices to small businesses, freelancers and other people seeking temporary working spaces, sold the shares at a higher price than in its previous round, which valued it at about $16 billion a year ago.