Elon Musk has long railed against the U.S. government, saying a crushing number of federal probes and safety programs have stymied Tesla, his electric car company, and its efforts to create fleets of robotaxis and other self-driving automobiles.

Investors seem to be growing worried that Elon Musk, for all his business acumen, is getting distracted, with his fingers in too many pies.

Tesla's Cybercab, or robotaxi, was announced last October and is due to hit the roads in Texas this June as part of a trial roll-out.