What the article doesn't mention is that this happens very frequently during the year. The market was up 2ish% yesterday.
That happens even on days when the US doesn't elect a president.
That's the Guardian's way of saying Trump's win boosted the stock market. I am pleased that my S&P 500 index fund rose 2.5% yesterday and am not disturbed that very rich people had large dollar gains.
Many on HN have likely benefited just like you.
What is your point?
The point is that most people would regard the stock market rising as good news, but the Guardian is trying to frame it as bad, IMO appealing to envy.