The Financial Conduct Authority has fined Deutsche Bank £4.7m for incorrectly reporting financial transactions for six years between November 2007 and April 2013.
The FCA said Deutsche Bank failed to properly report more than 29 million Equity Swap Contracts for Difference transactions. It previously received a private warning from the regulator relating to similar transaction reporting failures.
The FCA said it is particularly concerned about the breaches because it has provided firms with extensive guidance on reporting. It noted it has already taken action against several other firms. The regulator views such reports as key tools in identifying insider trading and other suspected market abuse.
FCA director of enforcement and financial crime Tracey McDermott said: "Effective market surveillance is critical to maintain the integrity of our markets and depends on accurate and timely reporting of transactions. Deutsche is a major market participant responsible for reporting millions of transactions every year.
Effective market surveillance is critical to maintain the integrity of our markets and depends on accurate and timely reporting
"We have repeatedly highlighted the importance of accurate transaction reporting and taken enforcement action against a number of firms. There is simply no excuse for Deutsche's failure to get this right. Other firms should be in no doubt about our continued focus on this issue."
Deutsche agreed to settle at an early stage of the investigation, and received a 30% reduction of the fine.