Changes proposed by the International Accounting Standards Board could impair the ability of companies to recognise pension surpluses on the balance sheet, trapping excess payments in the pension fund.

Problems could prove particularly acute since recent stock market rises and improving bond yields helped reduce deficits, and put many companies on track to report a surplus soon.

At present, companies with a pension scheme in surplus can report the excess on the balance sheet if they can use it to reduce contributions. But under the changes proposed by the IASB through its review of IAS19, companies would find it difficult to claim surpluses on their balance sheets.

The draft proposals could take effect from next year.

Actuaries say that businesses are concerned about the rules and what effect they will have on their balance sheets.

Alex Waite, partner at actuary Lane, Clark & Peacock, said: ‘The proposals will stop companies contributing. The message is “think very carefully before you put your money into the pension fund”.

‘Companies will have a lot of explaining to shareholders to do if they trap money in a fund that they can’t touch,’ he added.

According to Martin O’Donovan, assistant director, policy and technical, at the Association of Corporate Treasurers, there is a better prospect of funds reporting a surplus over the next five years. So treasurers are looking at alternative ways of dealing with their deficit that won’t tie up company cashflow in the future.

‘The market fluctuates so much that those in deficit now could report a surplus in the next five years,’ said O’Donovan.

‘Conditional guarantees with fund trustees will become more common,’ he added.

A spokeswoman for the IASB said the plans were ‘merely an interpretation. The interpretations committee can’t amend standards’. Consultation on the move is open until 31 October.