He doesn't really need to sell though does he. Like imagine if ceo's came out to trade and give public announcements beforehand to build trust. For instance an Apple Executive trading directly with Musk equal valued shares and telling the populous it is a good thing as these executives are showing that they believe strongly in these other companies. Next thing you know he's got his investments varied across every field, and should maintain a portfolio matching the market average whether one field struggles for a bit or not. It "looks" like they are all showing faith in each other's future gains, but in reality is is diversifying their portfolio to ensure no large setbacks