Natixis, France’s fourth-largest bank, on Wednesday night said it would launch a €3.7bn ($5.9bn) rights issue after revealing that it would make €1.5bn of subprime-related writedowns when it announces its first-half results next month.

The troubled bank, which has lost 70 per cent of its value during the past 12 months, said in a statement that the latest writedown was because of exposure to US monoline insurers and a portfolio of instruments including collateralised debt obligations.