And so Spark, which formally announced on Monday its two latest investment funds, with a combined $1 billion in capital, has backed Cruise as well as some other eclectic companies: an upstart stock exchange called IEX, and Mark43, whose software helps police departments organize their records. Those investments sit alongside bets on more recognizable companies like Slack, the popular messaging software, and Wayfair, the online home furnishings retailer, which is now publicly traded.

“No one knows what the next big platform is,” Nabeel Hyatt, a Spark partner, said. “Now is a new market time.”

The firm, which has expanded to San Francisco and New York from its home base in Boston, has had some big wins. Tumblr, one of the firm’s first investments, was acquired by Yahoo for almost $1 billion. Twitter, where Spark also got in on the ground floor, went public in 2013 with a market valuation of over $14 billion. And Oculus, the maker of virtual reality headsets, sold itself to Facebook for $2 billion.

Not all of Spark’s bets have paid off. The firm was an early backer of Foursquare, a location-based start-up that has lost much of its popularity and whose valuation was cut in half by January.

Many of the best-known venture capital firms live on the fabled Sand Hill Road in Menlo Park, Calif., but Spark was born in Boston in 2005. Two veteran venture capitalists, Santo Politi and Todd Dagres, said they believed that as the dot-com bust receded from memory, the time had come to make bets on consumer internet companies once more. And they persuaded Bijan Sabet, a longtime acquaintance and entrepreneur, to come on board.