Tech pioneer Elon Musk has denied being high on marijuana when he published a series of tweets that prompted an investigation by a US federal regulatory agency.
Stress was taking a heavy toll on him personally, he admitted while telling an interviewer the pressures of the the past 12 months had been “excruciating”.
The New York Times reports the chief executive of electric car maker Tesla alternated between laughter and tears during an interview in which he said he was working up to 120 hours a week and sometimes took the sedative Ambien to get to sleep.
But he denied being “on weed” when he posted news of a potential $US72 billion ($A99 billion) buyout of the publicly held company.
“This past year has been the most difficult and painful year of my career,” he said.
“It was excruciating.”
The interview offered rare insights into Musk’s personal life and thinking.
He stood by his tweet last week saying he might take Tesla private and that he had secured the funding to do so.
Asked if he regretted it, he said: “Why would I?”
Musk has a reputation for being an eccentric visionary but his sudden announcement of a potential buyout raised a huge ruckus and pushed Tesla’s shares up 11 per cent in a day.
They have since fallen back but remain elevated.
The Wall Street Journal reported that government regulators have subpoenaed Tesla as they dig deeper into his disclosure of the potential buyout.
He said in the interview that he had wanted to offer a roughly 20 per cent premium over where the stock had been trading, which would have been about $US419.
He decided to round up to $US420 – a number that is code for marijuana.
“It seemed like better karma at 420 dollars than at 419 dollars,” he said.
“But I was not on weed, to be clear. Weed is not helpful for productivity.
“There’s a reason for the word ‘stoned’. You just sit there like a stone on weed.”
He said he fired off the tweet while on his way to an airport and his reference to having secured funding referred to a potential investment by Saudi Arabia’s government fund.
The 47-year-old said he sometimes did not leave the Tesla factory for three or four days straight and he had not taken off more than a week at a time since he was sick with malaria in 2001.
His social media antics have raised plenty of eyebrows. He has berated analysts and falsely accused a cave diver of being a pedophile after the man was sceptical about a mini-submarine Musk sent to possibly help rescue young football players from a flooded cave in Thailand.
He later apologised for the remark.
The report cited sources saying Tesla is trying to find an executive to help relieve some of the pressure on Musk.
He said he did not intend to give up his roles as chairman and CEO but if there was someone who could do the job better, “they can have the reins right now”.