Elon Musk is the CEO of SpaceX and Tesla, an electric car manufacturer and energy provider. Born in South Africa, Musk made his way to the U.S. during the early 1990s and founded X.com, which later became PayPal.

A video circulating online appeared to show a Tesla Model Y robotaxi with no safety monitor inside driving on Austin streets.

Using Tesla's current shares outstanding (3.5 billion) and the market cap target suggests a share price of about $2,400. That's nearly 6 times the current share price, which is extremely ambitious. (Note that 424 million shares multiplied by $2,400 gets you to over $1 trillion.)

Tesla stock closed at a fresh record high on Tuesday, completing a monthslong rebound from severe losses earlier in the year.

Elon Musk's net worth hits $681 billion, more than double Google co-founder Larry Page's $249 billion wealth, as Tesla's stock surge widens the billionaire gap.

Tesla stock staged a massive rebound, with shares climbing 120% from their low in April on a handful of positive catalysts.

Tesla ( TSLA +3.44%) stock jumped 4.5% through 1:45 p.m. ET Thursday on some apparently bad news -- that might turn out to be good news for Tesla stock, and for SpaceX stock, too ( once SpaceX IPOs ).

Tesla's Full Self-Driving software is still ironing out minor issues like being stunlocked by engilding rays of sunlight.