About two years ago, I asked someone that very same question.
They told me that the day-to-day market purchases aren’t done by people. They’re done by computer algorithms.
The crash a couple of years ago? Yeah, a computer went haywire and started selling. Other computers saw the trend and started selling. It was a technical glitch.
Yes, humans run the computers, but the majority of the work is done on autopilot.
That is why I quit watching the stock market. It used to be a good reflection of the economy, but it’s not any more. Now, what you’re watching are a series of computer programs reacting to one another.
The human trades can influence the market (cause reactions in the programs) - if there are enough of them done at one time.
Simple concept. All shares outstanding are valued at the last sale, no matter how small the volume in the trade. This makes it easy to manipulate the price. Ever read “Wall Street Insider’ by Richard Nye? An excellent book written back in 1973 or 1974.