Why Are Securities Markets So Erratic?

Securities markets are generally erratic.  However, when you think about it, they really ought to be calmer than they are.

Institutional investors and advisers are considered professionals. They’re the experts who account for  80%, and often  more, of all trades and activity. Why then should the markets behave erratically?

Pros ought to know what they are doing, unlike the other 20% or so of the public amateur investors who blindly follow the pros.

However, Wall Street "wizards" invariably act in a mob-like manner.

They still make their millions, simply because they are ensconced as Wall Street inside players. (See the Earl J. Weinreb NewsHole® comments and @BusinessNewshole at Twitter.)