The level of underfunding of defined benefit pension plans of US corporations has jumped 27 per cent to a record $353.7bn, raising fears that the agency that insures these pension plans could face a widening of its own deficit.

The Pension Benefit Guaranty Corporation, said the data came from 2004 reports submitted by April 15, representing 1,108 pension plans. The plans had an average funded ratio of 69 per cent, it said.