Quote from whitster:
golf clap
a big part of chaos theory is how (relatively) small perturbations in a system can have HYOOGE (and somewhat unpredictable) effect.
the classic "butterfly flapping its wings in bolivia causing a hurricane in guatemala"... thang
again, market behavior is HUMAN behavior.
the market is a giant feedback system. market makers and institutions are generally selling strength and buying weakness, retail traders are chasing ticks where their (not so robust) indicator is saying "breakout" or some such. different people with different NEEDS (for example, a hedging commercial producer), entering trades for different reasons, based on different analysis.
it can often seem random. it is never RANDOM. it is COMPLEX
there is a difference
and in the case of many market crashes (like you mention), it was often SMALL perturbations that had effects that, as you put it, are basically statistically almost impossible (much like a scalper being consistently profitable is not possible if trades are random)...
also note that the market has never (to my knowledge) gone UP 20% in a day, or had the sort of extreme one-two-three day market moves UP vs. the moves down.
the drift bias is (obviously) up. that's a function of the fact that wealth is created in the system (stock market) , since stocks are a proxy for businesses, that also create wealth.
yet, despite the drift bias being up, these extreme and basically statistically impossible crashes happen with NO counterpart on the up side
that is because fear and panic are strong emotions.