In, surprisingly, The Guardian.
Today, online trading by retail investors is a huge industry. In the UK, many thousands of amateur traders log on each day in an effort to beat the market – that restless sum of countless, competing bets on the value of stuff. In the main, they fail. And fail quickly.
Quite. What the EMH is trying to tell us is that markets process the information about what prices should be in a market efficiently. Thus, unless you have information which is not known to the market in general (something which weak versions of the EMH allow and strong versions do not) you cannot beat the market.
And as you as an individual trader are most unlikely to have such information even the weak EMH says that you shouldn\’t try to beat said market. Because you won\’t.
Optimists reckon that 80% of amateur traders lose money, which many have borrowed. The figure is probably closer to 90%.
There we go, real world proof that the EMH is correct.