Questions have been raised about the fairness of non-disclosure agreements between asset managers and pension funds.
Pension schemes argue that the practice of asset managers coercing funds into signing the agreements is uncompetitive and prevents them from securing the best deals for their members.
By contrast, asset managers are defending their commercial right to require confidentiality.
The practice of imposing confidentiality agreements over fees means pension funds are unable to compare how much they are being charged by fund managers, potentially exposing them to high costs.
The agreements are signed when funds appoint a company to manage their assets and it is this practice, critics believe, that enables fund managers to overcharge their clients.
Concerns are particularly high in the public sector where pension plans are effectively funded by the taxpayer.
David Blake, director of the Pensions Institute at Cass Business School in London, told the Financial Times that not being able to compare fee deals is an "outrage."