Tesla announced this afternoon that CEO and co-founder Elon Musk exercised 532,000 options of the company this week, increasing his holding by about $100 million worth of market value. The transaction was very much "in the money," as they say: the options were exercised at $6.63 apiece, according to an SEC filing, while Tesla stock is trading around $192 as of market close on Friday — so that works out to a profit of around $185 a share. Musk used "more than $50 million" in cash to cover the exercise price and the associated taxes, according to the announcement.

This isn't the kind of thing you necessarily announce with a press blast unless you want to boost confidence in the company, and Tesla can always use a boost: Model X production can't go fast enough, and the make-or-break Model 3 is expected to be shown in March. Musk's total holding is now in the neighborhood of 29 million shares — roughly 22 percent of the company. He has another 2.82 million options in the bank that he can exercise at a future date.