In its consultation paper CP12/10 the FSA proposes reducing the cap on the rate, which is used to indicate typical investment growth, by two per cent.
This is calculated by PricewaterhouseCoopers based on a fund invested two thirds in equities and one third in bonds, regarded as a typical investment mix.
However, Aegon believes it is no longer appropriate to base the rate on an "arbitrary investment mix". It feels the move to asset-specific projection rates should mean rates reflect likely returns on the actual asset mix of each fund.

The capping of the rate at five per cent is "unreasonably pessimistic" for equity-based funds, said Aegon, as the PwC analysis suggests returns of between 6.5 per cent and eight per cent in the medium to long term.
Steven Cameron, Aegon's head of regulatory strategy, said: "Aegon agrees it is unhelpful to give customers unrealistically high expectations of future returns. But there's also a risk of consumer detriment if the FSA forces unrealistically low projection rates on the industry.
"Artificially capping projection rates for equity-based funds will make it much harder to select between funds on a risk/return basis. Under the FSA proposals, customers may be presented with little extra growth prospects from equities over bonds but will be aware of the extra risks."
He proposed an alternative approach which involved ensuring the projection rate reflected the underlying assets in each fund. This asset-specific approach meant consumer got a realistic indication of what they may get back without the risk of consumer detriment.