"This belief is unreasonable from ourselves as fund managers and also from investors and as you start looking into funds you should not seek that type of outperformance.
"The industry is flawed for promising it as it is a statistical improbability," Bonham Carter added.
His comments were made at an investment dinner hosted by Jupiter at Home House where he admitted Jupiter itself had been guilty of perpetuating the unrealistic expectations.
"There is a tendency to sack people at the bottom and hire at the top, to launch funds at the wrong time of asset cycles and close them at the bottom of them."
Bonham Carter also said that while he prefers not to forecast where possible, he thinks a "hippo market" is going to be the norm for the time being.
A term coined by Bonham Carter at a previous Jupiter event, the hippo market refers to times when "indices wallow around doing very little over the long term, but have significant short term bouts of volatility".
