and couldn’t just do it because of a previously appointed fed chair
Ok this tells me you don't know how any of that works...
However he can’t just pick a day and say “this is the day I’m going to make the stock market crash to make my opponents look bad.”
No? what if he were to sign an executive order banning SpaceX from gov contracts (something he already did for Anthropic), do you think SpaceX stock would be unchanged?