PALO ALTO — Founders Fund, the San Francisco-based venture capital firm that has invested in Airbnb Inc., SpaceX Corp. and Hampton Creek Foods Inc., closed a billion-dollar fund last week, tapping Cooley for counsel on the fund formation.

The firm, which invests in companies of all stages across a range of sectors, was founded in 2005 by former PayPal executives Peter Thiel and Ken Howery with just $50 million. Prior to this fund, its fifth, Founders Fund’s most recent raise was for $625 million in 2011. In January, the firm was rumored to be raising $750 million to be applied to new investments and additional rounds for current holdings.