Munster predicted a one-in-three chance that Musk will actually take Tesla private. "Funding secured", tweeted Musk just before 1 pm Eastern. Others interpreted the tweet as a joke, in specific Musk's reference to "420": a popularized reference to the consumption of cannabis by the marijuana culture.
Tesla's shares were up 6.5% at $363.46. A price of US$420 a share would value the company at US$72b, nearly double Ford.
Musk has lashed out at critics and investors who have shorted the stock, going so far as to call one prominent critic's employer to silence him, and refusing to take a hard question from a financial analyst in the company's June shareholder meeting.
Tesla shares were already trading higher on a report of a new stake from the Saudi Arabia sovereign wealth fund .
Tesla has had more than its share of ups and downs over the past few months, due to an intense focus on production rates and sales figures for Tesla's mass-market Model 3 electric vehicle.
In a Twitter direct message to Ars Technica, Musk confirmed he was serious about the proposal.
Tesla did not immediately respond to a request for confirmation or clarification. Today's Tesla rally could make life more hard for shorts because brokers often ask shorts to put up more money when a stock they've shorted rises in value.
Largest wildfire in California history
Steele's district includes the towns that still have fire above them, and in some places, creeping down the ridge. That fire, which is now 43% contained, has destroyed more than 1,000 homes and burned over 160,000 acres.
European Union acts to protect firms from Donald Trump's sanctions against Iran
He again justified leaving the nuclear agreement (JCPOA) and left the door open to negotiations for new deal in the future. For his part, Rouhani praised Europe for "resisting the Americans" in its call "to join the regime of sanctions".
Smoking banned in all public housing
The ban was first announced back in November 2016, but housing agencies had until July 31, 2018 to enact the ban. Tenants with repeated violations could be evicted, according to HUD's website .
Musk said the final decision on whether the company goes private will be subject to a shareholder vote. Depending on the follow-through, or lack thereof, Musk's statements could cause problems with the Securities and Exchange Commission.
After Musk, the next largest shareholders in Tesla are the mutual fund giants T. Rowe Price and Fidelity, with stakes of more than 9% and 8%, respectively, according to Thomas Reuters Eikon.
The electric vehicle maker reported revenue of $4 billion in the second quarter of 2018, with $2.2 billion in cash in hand.
Musk has said he expects Tesla to begin being profitable in the third quarter of 2018.
And yet it also left many questions unanswered, namely how Musk - who owns nearly 20 percent of the company - would be able to come up with the $66 billion necessary to complete the transaction.
Tesla went public in 2010.
Taking Tesla private could remove some of the pressure on the closely watched company.