Finance jargon is impenetrable. Aren't you supposed to gamble with a fixed percentage of your money in case a long tail event happens? From an outsider's point

Finance jargon is impenetrable. Aren't you supposed to gamble with a fixed percentage of your money in case a long tail event happens? From an outsider's point of view, that seems like rule number one. Questions about NASDAQ: - What is NASDAQ? Wikipedia says they're a "stock exchange", which supposedly means they provide a place for people to trade in stocks and bonds and various other "securities". - How was NASDAQ affected by this guy's decisions? Are they trading something? Cheers.