There is a common, fairly logical story about market efficiency: the more people look at a stock, the more efficiently it should be priced. Attention brings trading, and trading corrects mispricing. Therefore, highly watched stocks should be harder places to find anomalies. QED. (quod erat demonstrandum, for those without the benefit of a classical education.) […]

The rise of zero-days-to-expiry options has produced an amusing mixture of excitement, moral panic, and bad intuition. Some people see 0DTEs as the new day-trading casino. Others see them as the purest possible form of volatility trading. Both views contain some truth, but neither is very useful on its own. The more interesting question is […]

Most of what we believe to be true in the markets isn’t true. It takes a long time to accumulate enough observations of an effect that by the time we believe in it; it has often ceased to be true. Most so-called market wisdom is really a collection of statements that are true just often […]

GOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOAL!!!!!!!!!!!!!!!!!!!! (The World Cup and Equity Markets)   No-one now really believes humans are rational, either individually or in aggregate. And the entire field of behavioral finance is predicated on this fact. The effects that relate to the market have often been strange. Researchers have linked stock returns to holidays, Netflix, the doomsday clock, cloud […]

Markets are supposed to respond to information. New facts arrive, prices adjust, some bald man on CNBC opines and we all move on. But that tidy story assumes something big: that investors are always paying attention. Anyone who works with other people (or really just lives in the world) knows that in reality, attention is […]