ABB, the Swiss-Swedish manufacturing group, has sold its reinsurance arm Sirius to US-based White Mountains Insurance Group for $425m (€347m), in a transaction which was three years in the making and at a book loss of $150m.

Deutsche Bank was hired in 2000 to look at ABB's non-core reinsurance portfolio but the terrorist attacks of September 11, 2001 halted any sale. Deutsche began pre-marketing Sirius a year ago.