[thebigspacefuck]

A stock is a piece of a company. That company should be creating value and that value should be worth money, maybe revenue or assets. The price of a company goes up because it is either worth more today than it was yesterday or people believe it will be worth more tomorrow than it is today. Usually people that own a company are trying to create more and more value. It's human nature bubbling up to the top. Why would the stock market suddenly stop reflecting this value growth for absolutely no reason?

[alanfranzoni]

Because it may be (already) overpriced, and maybe somebody will stop investing in the stock? Because automatic systems (e.g. AI, HFT) will lessen investors' faith in the stock market? Because better investment opportunities come out?