$625/share as the margin call level? As I understand it there are some documents saying how many shares he has on margin, but nothing about the triggers.
As CEO of Tesla there are limitations on his ability to pledge his shares of Tesla stock? What limitations? I thought his limit was "number of shares he held"
Musk cannot pledge or sell his SpaceX shares without prior government approval, as doing so would violate a number of requirements related to SpaceX's government contracts? What clauses in what contracts? There may be clauses that prevent him from transacting shares to non-US citizens, but in general?
Yes, as CEO of a publicly traded company there are limitations on his ability to pledge his shares of that company's stock, and that limit is far less than "number of shares held." This is not a legal requirement; it is a de facto requirement relating to eligibility for the S&P 500 and of corporate governance requirements by many public pension funds and other large investors to buy a company's stock.
1: https://www.huffpost.com/entry/zuckerberg-twitter_n_4256014
Additionally, as CEO of Tesla there are limitations on his ability to pledge his shares of Tesla stock. It's unlikely that he's anywhere close to that threshold, but that is something he needs to watch for.
Also, Musk cannot pledge or sell his SpaceX shares without prior government approval, as doing so would violate a number of requirements related to SpaceX's government contracts.