Stock prices go through the floor because those with the money are influencing people like Trump to do what he has done.
Those with the billions will be buying up shares at a rate of knots and then will ensure that the value of their holdings increase at a rate of knots so that they become richer whilst the small investors and those whose pensions are tied up with share prices will continue to worry how they will make ends meet.

Usual tale --the rich get richer whilst the rest of us just do our best. Situation normal, nothing to worry about.