OK, so I subscribed to Dunn's website to get his actual numbers. His longest running fund goes back to 1984 and his avg annual return is 13.76% with a sharpe ratio of .55. If you had invested with him the last 3 years, his returns are negative. For Abraham, his annual returns since inception (which goes back 30 years) is 15.32% with a sharpe of .41. Again, if you had invested with him the last 3 years, your returns are negative. There is a common theme here among all the great CTA's and that is a bulk of their out performance came early on primarily in the 1980s and early 1990s. It should be noted that Dunn and Abraham are two of the best in the industry and their sharpes are both in line with that of the S&P 500 which is around .50. I am still waiting for someone to list another manager or managers who have avg annual returns > 20% with a track record greater then 10 years.
Apart from all this, size is also a meaningful input... The best funds like Bridgewater's PureAlpha and Baupost have produced 13% and 16% annual returns since inception and they've been arnd since the 80s.
Ken Griffin says hedge funds under performing are those that lack deep level specialization, an example he gives they have a team that just trades European natural gas. ps as per Barry Ritholtz in US today there are more hedge funds than Taco Bells.
PS also as per Barry Ritholtz in 2008 Hedge Funds lost more money than they had ever made... https://assets.bwbx.io/av/users/iqjWHBFdfxIU/vTASHpI1uMJ8/v3.mp3