[bankwalker]

a sudden increase (say 10%) in the implied volatility of slightly out-of-the-money puts seemed to predict a rise in call prices within a few minutes

That has always been the case and is due to arbitrage. Some big trading companies take advantage of that all day long and you'll never be quick enough to take it from them.

[RoosterRedux]

That’s not entirely correct, and here’s why. Tiny mice can thrive on the floor of the elephant cage, surviving on crumbs and bits of nuts too small for the elephants to notice.

I know this because I spent most of my career on Wall Street with a major firm—not as a trader, but on the investment banking side. While my primary role was working on deals, I was familiar with how the traders operated, and there were always plenty of crumbs falling to the floor.

These days, I still make my living in the securities business—as a private investor.