Originally Posted by
ttango9001
Suppose somebody is an expert in a certain sport or league and has a long term yield of 5-6% in highly liquid mature markets, with an average number of around 200 picks yearly. With such a low turnover, and assuming he is flat betting 1% of his bankroll in each bet he would have a return on capital of around 13% yearly. Now, if his bankroll is not big enough, this interest rate although impressive by most standards, is simply not enough to cover living expenses. In this case, generating an extra source of income by selling his picks is a very sensible strategy. Considering that we are talking about highly liquid markets where his clients money are not likely to have any real impact on his profits (afterall he can still bet his picks before he sends them out), this would also make sense even if he had a much bigger bankroll. In effect, it's very similar to managing other people's money and charging a comission for the service.
Of course, 99.9% of all the "tipster" sites out there are complete garbage, but this doesn't mean that there are no legitimate services that perform consistently good over the years.