Tesla Chief Executive Elon Musk has been filmed smoking marijuana and wielding a sword on a webcast, just hours before the automaker said its recently-appointed accounting chief would leave, the latest in a string of unusual behaviour and executive departures that have stunned investors.
Shares of the electric carmaker tumbled more than 6 per cent to $US263.24, with investors on edge after a tumultuous August during which Musk proposed and then abruptly pulled the plug on a go-private deal.
Chief Accounting Officer Dave Morton resigned after just one month in the job because of discomfort with the attention on the company and pace of work during that time, Tesla said in a filing on Friday.
It later said that Chief People Officer Gaby Toledano would not return from a leave of absence, just over a year after joining.
Later on Friday, Tesla named a new president of automotive operations, promoting former Daimler truck executive Jerome Guillen into the role overseeing all automotive operations and reporting to Musk.
Morton and Toledano, whose departures come shortly after the US Securities and Exchange Commission opened an inquiry into Musk's aborted privatisation plan, join dozens of senior executives who have left Tesla.
On Thursday, Musk was filmed drinking whiskey, briefly smoking marijuana and wielding a Samurai sword during a 2-1/2-hour live Web show with comedian Joe Rogan that swiftly spread across social media.
Taking a puff from a joint, which Rogan said was a blend of tobacco and marijuana and legal in California, Musk said he "almost never" smoked.
"I don't actually notice any effect ... I don't find that it is very good for productivity," Musk said.
It was the latest in a string of unconventional behaviour by the billionaire South African native who is also CEO of rocket startup SpaceX.
Even before Musk's surprise August 7 tweet that he had funding "secured" for a go-private deal, Tesla had been under scrutiny from investors, analysts and short-sellers as it worked to hit production targets and slow its cash burn.
