[mech765]

I think that calling it random is a mischaractetization. It's more of "market movements are caused by a combination of millions of people trading on millions of narratives and data points, and when news breaks, much of the new associated information has already been priced in."

[jfengel]

I would call it random in a thermodynamic sense. You can't have all of the relevant information. You know the long term fairly well but the short term is noise. Most supposed jolts are smaller than you imagine, and can disappear before any noticeable effect.