"Yes, might take Tesla private", he said. "Funding secured", Musk tweeted shortly before 1 p.m. on Tuesday.
Shortly after, Mr Musk responded to replies to his tweet, asking if he would remain in control of the company.
Tesla has been publicly traded since 2010, and has seen its share price rise from just under $20 then to $360 at time of writing. The company had a market value of $58bn as of Monday's close.
Musk's other company, aerospace firm SpaceX, is privately owned.
His asking price of $420 would be 22 percent of Monday's closing share price, and almost 9 percent above the stock's all-time closing high of $385.
And according to a report by The Financial Times, Saudi Arabia's sovereign wealth fund - which is overseen by crown prince Mohammed bin Salman - has reportedly invested heavily in Tesla, building up a stake between 3% to 5%.
Musk's tweet came two weeks after Tesla revealed it had burned through $739.5 million in cash on its way to a record $717.5 million net loss in the second quarter, as it cranked out more electric cars. He implied the funding values the company at $420 a share.
The tweets have added to speculation about Tesla, which is spending heavily as it ramps up production of its latest vehicle, the Model 3.
George Galliers of Evercore ISI said he believed the tweet was serious. "Given his historic frustration with short sellers, analysts and certain parts of the press, it is perhaps also not surprising that he has given consideration to taking the company private", Galliers said.