If you can tank world wide stock markets at will, why not use that power to your advantage? Multiply the fortunes of yourself and of those you need to stay in power.
Might well offset the effects of any sanctions the outside world could possibly impose on you. The whole affair would be a can’t-lose scenario for you, and you’d be winning even if you failed to reach any of your other goals.
Could he have done it? Any indications that he did or didn’t? Is there a limit to the possible payoff for such a scheme?