Investors are marking down the value of FTSE 100 companies with defined benefit pension liabilities on their balance sheets by 20% compared with similar companies without the obligations, research has found.

A report commissioned by de-risking specialist Pension Insurance Corporation and carried out by Llewellyn Consulting showed that even if a pension fund is in surplus, investors will mark the value of a company down due to the volatility that a DB pension scheme brings to a balance sheet.