When it comes to car companies, the way the stocks are sold and held are usually done in such a way that allows the founders to maintain some say in the company. With the exception of selling the company off for profit, this is usually done so that they maintain control over the decisions that go on- even if they may not be involved in a corporate role. With the financial crises over the past decade or so, a lot of these founders have eventually yielded and sold their stock options in favour of cash.
Elon Musk’s own baby, Tesla, has seen some pretty sharp increases in stock value- but Musk has chosen to retain his 22% stake in the company. As reported by the Los Angeles Times, Musk owns 29 million shares at around USD 191.20 a pop. While he could have sold a large proportion of these shares in order to cover taxes and fund other projects, he chose to do so with his existing finances rather than lose his controlling interest.