Tesla shares were last up 1.4 per cent at $555 after trading was closed on Tuesday, reports CNBC.
The milestone came less than a month after Tesla's stock crossed $420 a price Musk tweeted last year which put him in much trouble.
The $100 billion valuation must stay for both one-month and six-month average in order to help Musk get first of 12 tranches of $346 million in a record-breaking pay package.
Tesla is currently valued more than Ford Motor and General Motors combined.
Musk lost his position as Tesla Chairman after posting a notorious tweet in August last year that he was "considering taking Tesla private at $420. Funding secured".
The US Securities and Exchange Commission (SEC) sued Musk over the tweet, saying he misled investors by claiming falsely he had lined up funding for the take-private transaction.
Musk reached a settlement with the SEC, agreeing to give up his role as Tesla Chairman and pay a $20 million fine.
Tesla surprised Wall Street in October by registering a profitable third quarter with a total revenue of $6.3 billion riding on sales of its Model S, Model X and Model 3 electric cars.
In the third quarter, automotive revenues were $5.35 billion. Tesla said it expected to deliver between 360,000 and 400,000 vehicles this year, representing 45-65 per cent growth.
( With inputs from IANS )