The collective deficit of the UK's company pension schemes hit its highest level last month since June 2003.
Deficits have pushed some companies to close their schemes
According to the Pension Protection Fund (PPF) the deficit rose in February from £81 billion to £98 billion.
Each month the PPF analyses the financial position of nearly 7,800 final salary pension schemes, mainly in the private sector.
It blamed the change on a fall in the return on government bonds, which made pensions more expensive to finance.
February was the fourth month in on a row that the collective deficit of the schemes has become worse.
This time last year they had a combined surplus of just over £3 billion.
6,702 schemes are currently in deficit, with just 1,046, or 14%, still showing a surplus.
However the PPF stressed that monthly changes in pension scheme finances are extremely volatile, depending on the rise and fall in the price of shares and bonds on the international financial markets.