Trading is taking advantage of the rest of the market. You need to have a difference in either beliefs or preferences relative to the rest of the market, other

Trading is taking advantage of the rest of the market. You need to have a difference in either beliefs or preferences relative to the rest of the market, otherwise the winning move is always "Do not transact." [+] Insider trading is illegal because it takes advantage of one's employer. You are allowed to use material non-public information to beat the living daylights out of everyone else on Wall Street as long as you don't have a fiduciary duty to the source of the information. This includes doing things like e.g. performing image recognition on photos taken by spy satellites to count the number of cars in WalMart parking lots and thereby arrive at their quarterly sales numbers before they're released publicly. (That was an actual thing that was done.) [ + ] Edit: Actually, on re-reading this, it is glib but false, in consequential ways. Long story and I've already pulled an all-nighter. Some other day.