Britain’s Financial Conduct Authority said, managers of four trillion pounds in assets must clearly spell out their investment objectives to customers and explain why they use a benchmark to measure performance.

The FCA published a set of new rules for asset managers, saying its review of the market found “weak price competition” leading to lower returns for savers.

It was the second batch of remedies or rule changes following publication of its market study into asset management in November 2015 to improve “value for money” for investors in funds that have been accused of being opaque regarding fees and charges.

The latest batch require fund managers to clarify how performance of the fund is measured, and show that where a performance fee is specified, it must be calculated based on the scheme’s performance after the deduction of all other fees.