One of arguments for paying a money manager or a fund to manage one's account is that they are professionals, they buy lower and sell higher than an individual trader. Well, here is a counterargument: PSAGOT, Israel's largest fund management house, is under investigation. Its nostro manager has been playing the market in his personal account AGAINST the fund, buying for example some derivative in the morning, then driving up its price by large purchases by the fund, and them selling high his own holdings. A cakedance. His profits were in the millions. Those millions were stolen from those investors that ceded the management of their savings to a "professional".
Fortunately, I discovered this phenomenon about five years ago (I noticed it but to say the truth, I was never 100% sure that my suspicions were true, one thinks this may be is a special case, or as usual, one tends to accept that they have more information and there are things ignored by an individual and so on). Since then, I do everything by myself.
The only fund manager I know who says that professional managers have no alpha is Falkenstein. He has the old American Protestant virtues of honesty, integrity and generosity.