Volatile pension schemes are now in deficit again.
The UK's final salary pension schemes have fallen back into the red according to the Pension Protection Fund (PPF).
Its latest analysis of the finances of nearly 7,800 schemes shows that they had an overall deficit of £24.1bn at the end of July.
That was a deterioration from a surplus of £8.3bn in June and a much larger surplus of £83.3bn in July last year.
Schemes are weaker because the cost of providing future pensions has been rising, while share prices have fallen.
"Over the past year, the negative impact of equities on scheme assets, combined with falling bond yields, have led to an overall worsening of the funding position," the PPF explained.
"With lower bond yields resulting in a 8.6% increase in aggregate liabilities, while weaker equities have reduced assets by 7.4%," it added.
Pension scheme finances are very volatile.
After falling into the red at the end of last year, schemes recovered and moved into the black during April, May and June.
Now they have taken a turn for the worse.
Last week the actuarial firm Lane Clark and Peacock found that the pension schemes of companies in the FTSE 100 index had a collective deficit of £41bn in mid-July.
It said they had suffered the biggest swing in their financial position since 2002.
But accountancy firm KPMG said the situation could lead to the trustees of many big schemes putting pressure on their employers to inject more cash into their schemes.
"We are heading for a "pensions crunch" as nervous trustees demand more cash from companies just as those companies have less of it," said KPMG partner Mike Smedley.
After conducting its own scrutiny of the accounts of firms in the FTSE 100 share index, KPMG came to the conclusion that a minority could not afford to pay off their pension fund deficits.
"15% of the sample are unable to clear them within any realistic timeframe without diverting cash from elsewhere," said Mr Smedley.