US mortgage turmoil hit investor confidence on the other side of the Atlantic on Wednesday as details emerged of a German government rescue of a domestic lender that suffered heavy losses on subprime investments.

The rescue of IKB, a specialist lender based in Düsseldorf, began on Sunday when Peer Steinbrück, German finance minister, called top banking executives to discuss a bail-out. According to people who took part in the conference call, Jochen Sanio, head of Germany’s financial regulator, is said to have warned of the worst banking crisis since 1931.