Shares in Wendel Investment, France’s oldest and grandest industrial dynasty, fell by 22 per cent on Friday after Standard & Poor’s the ratings agency, downgraded its credit rating to junk.

Late on Thursday, S&P cut Wendel’s long-term rating to below investment grade, citing: “the exceptionally challenging financial market conditions” which had weakened the company’s financial profile “beyond what is tolerable for an investment-grade rating”.