While we're here: How do real-world incentive structures interact with the EMH? In the same way that "No one was ever fired for buying IBM", is it true that "No one was ever fired for selling when everyone else was"? And would that mean someone without these external social incentives will have an edge on the market? For example, what about a rule like "put money into an index fund whenever the market went down for X consecutive days and everyone is sufficiently gloomy"?

My family has been investing for as far back as anyone can remember, and consistently beating the market for as far back as anyone can remember. Hell, my mother compares herself to the indices -- which makes perfect sense: if you're not beating the S&P 500, you may as well just buy whatever is on that. She's not buying whatever is on that. We have methods that have been handed down for as far back as anyone can remember, supplemented by the books that back up our methods, some of which are about exploiting systemic holes in the way large funds work -- relative legibility, inability of large funds to invest in small companies, etc. So no. (Disclaimer: I haven't invested at all because I don't have the money to. Once I have a regular and sufficiently large income, I plan to stick it in an index fund until I've joined an investment club, spent several years studying the methods, etc., and only start picking stocks after that.)