In an Aug. 16 interview with the New York Times, Elon Musk revealed that he fired off the fateful tweet saying he was considering taking Tesla private while driving himself to the airport. He says that he’d wanted to offer a roughly 20% premium over the price at the time for the electric car company’s stock. As he sat in his car in California, midday Aug. 7, that would have been $419. Then he decided to round it up to $420, saying his funding for privatization was secured.
That extra $1 added more than $170 million to the price he would need to pay. He was then valuing the company at about $71.6 billion.