People living in Telford face the prospect of having to pay more council tax to meet a £53m deficit in Telford & Wrekin Borough Council's pension fund.
The value of the council's pension fund assets has fallen by £38m due to a drop in the stock market.
However the council's liabilities have risen, creating a £53m black hole.
Council employees pensions are guaranteed by law so finance chiefs now have to find the extra money from somewhere.
Councillors are considering how to meet the shortfall without cutting services and a council tax rise remains a strong possibility.