DETROIT -- General Motors said Friday that it is paying $2.1 billion to buy out Japanese tech investment firm Softbank's stake in the Detroit automaker's Cruise autonomous vehicle subsidiary.

       Softbank paid $2.25 billion for a 20% stake in Cruise in 2018 as part of a wave of investment in self-driving technology.

       GM also said it is making an additional $1.35 billion investment in Cruise, in which it acquired a majority stake in 2016. Others Cruise investors include Honda, Microsoft, mutual fund company T. Rowe Price, and Walmart.

       Cruise is operating a small fleet of autonomous vehicles in San Francisco that it opened to the general public at the beginning of February. GM expects to get a permit to charge passengers for autonomous rides this year.