The International Accounting Standards Board rejected calls for fundamental changes to its rules for defined benefit pension schemes, Reuters reported Dec. 8.

Critics believe that the global accounting body's rules unfairly increase pension deficits in such schemes because liabilities are measured according to bond yields, which have plunged to record lows for a prolonged period, according to the report. They say fewer assets should be needed to cover liabilities as many pension funds invest in shares offering higher returns than bonds.

But Chairman Hans Hoogervorst reportedly said in a speech that booking a profit from investments in shares before they are earned would be an inappropriate approach, adding that accounting rules must reflect risks to investors. However, he did acknowledge that the rules for pension schemes were a "bit out of date" amid a low interest rate environment.

The board, meanwhile, is looking at how rules could cater better for "hybrid" schemes, under which pension liabilities are defined more flexibly, Reuters reported.