The same is more or less true of bonds though, no? Bond value is determined by perceived credit risk and people's feelings about the future direction of interest rates in general. Of course, eventually if you're correct you do indeed get paid by the borrower with a bond. However, the stock market will eventually fall in line with realized earnings. The only real difference is that the bond market's time horizon is fixed, whereas the stock market can stay irrational for a finite, but arbitrary amount of time.