On Feb 5, I woke up to a great birthday present when the Stock Market crashed. Bitcoin and the 3 Major Indices dropped and the DOW dropped 666 points. But my trading account was in the green and it doubled my money overnight.
Previously I had bought VXX a product inverse of XIV. XIV dropped over 90% when the 3 major Indices dropped.
Many people lost their shirts and one guy on Reddit posted that he lost over $4 million of his own money as well as other people's money and he wasted 3 years building his fortune.
SVXY also mirrors the SP500 and UVXY is the inverse SP500.