What’s preventing Michael Saylor from putting in a massive short, and selling all his BTC?

This has been something that I have been curious about.

Even if Michael Saylor plans on owning/accumulating more BTC in the long run, why on earth would he not do this? Is there anything holding him back?

Put in a MASSIVE short, sell all of Microstrategy BTC holdings, price drops (from such a huge sale, and the fact that Microstrategy makes its first sale of BTC, which im sure would gain media attention & effect the price negatively) …hell, he can even make a quick post about how he is having doubts about BTC.

Make the price tank, cash out heavily on your short position, and then buy back all your BTC (and more) at a lower price?

Am I missing something? Or is this possible for him to do, but he just has not done it (yet) ?