MILAN (Bloomberg) — Unipol Gruppo Finanziario SpA, Italy's fourth-largest insurer, led a drop in the cost of protecting bonds sold by European insurers from default, according to traders of credit-default swaps.

Contracts linked to Unipol's subordinated debt tumbled 40 basis points to 110, the lowest in a year.

Swaps on the junior debt of Prudential Plc dropped 16.5 basis points to 131.5, while Standard Life Assurance Ltd.'s subordinated debt fell 18.5 to 131.5.