Turmoil in the US subprime mortgage market damped US sales at Experian, the credit checking and data group, in the first quarter of its financial year.

Revenues at LowerMyBills, Experian's US business that targets and provides customer leads to subprime mortgage lenders, fell more than 20 per cent in April-June, following an 8 per cent dip in the last quarter of 2006-07.