The FSA has fined spread betting firm City Index £490,000 for transaction-reporting failures.
The regulator says the firm failed to submit accurate reports in respect of more than two million transactions.
It says the failings occurred between November 2007 and September 2009 and represented nearly 60 per cent of the firm’s reportable transactions.
City Index failed to report approximately 55,000 transactions and reported around 1,970,000 transactions with one or more data fields completed improperly.
The FSA says these breaches occurred despite its repeated reminders to firms of their obligations to provide accurate data. Managing director of enforcement and financial crime Margaret Cole says: “City Index failed to report accurately a high proportion of its transactions for almost two years. This is a serious breach of our rules because it can have a damaging impact on our ability to detect and investigate suspected market abuse.”