Imro has slapped a £250,000 fine on Australia and New Zealand Banking Group for breaching its rules and the FSA Statements of Principal.
The breaches occurred between January 1997 and May 1999.
ANZ agreed to a settlement after it was judged to have failed to act with due skill care and diligence while managing customer portfolios, to keep proper records and to have adequate compliance arrangements.
The firm has already paid compensation of around £228,000 to 84 of its customers. It has since changed its procedures.