Chief executive Elon Musk seemed to question the big jump in Tesla stock that followed his car companys announced deal with Hertz, saying in a tweet that "no contract has been signed yet." But Hertz countered that deliveries have already started.

Hertz Global Holdings, the car-rental company founded with a dozen Ford Model Ts over a century ago, filed for bankruptcy late Friday after sweeping travel restrictions and the global economic collapse destroyed demand for its vehicles.