The Financial Industry Regulatory Authority has fined Barclays, Goldman Sachs and Merrill Lynch $1 million each for submitting incomplete and inaccurate information about securities trading, Bloomberg reports.

According to a statement issued by FINRA on Wednesday, the banks failed to provide “complete and accurate information about trades performed by the firms and their customers,” known as “blue sheet” data. Regulators use this information to investigate possible insider trading and market manipulation, according to Bloomberg.

“Blue sheets are mission-critical to conducting reviews and investigations of suspicious trading,” Cameron Funkhouser, the executive vice president and head of FINRA’s Office of Fraud Detection and Market Intelligence, said in a statement. “When firms fail to submit timely and accurate blue sheet data, it compromises the ability of every regulator to identify the perpetrators of illegal insider trading and other market abuses.”

According to FINRA, the firms’ violations included submissions that were missing some customer names and contact information and some transactions. Some submissions also contained incorrect name and contact information for several customers or inaccurate details of transactions.

The omissions and inaccuracies stem from problems with the firms’ electronic systems used to put together blue sheet data, according to FINRA. The regulator also found that the firms did not have in place sufficient audit systems that provide for accountability of blue sheet submissions.

According to FINRA, each of the firms named has a prior history of submitting inaccurate blue sheet data. The regulator has ordered each firm to conduct a comprehensive review of their systems and establish procedures designed to address and correct the violations.