Three broker-dealers have agreed to pay a total of $6 million in penalties to settle charges they provided the SEC with incomplete and inaccurate securities trading information.

The deficient information was in the form of “blue sheet data,” which the SEC uses to "carry out its enforcement and regulatory obligations, including the investigation of insider trading and other fraudulent activity," the agency said in a press release on Monday.

Citadel Securities LLC in Chicago, and Natixis Securities Americas LLC and MUFG Securities Americas Inc., both based in New York, submitted forms over several years that contained inaccurate or missing data; incorrect order execution times that failed to adjust for time zone changes; and incorrect or missing exchange codes, transaction type identifiers, opposing broker number and contra-party identifiers, the SEC said.

Citadel submitted incorrect data for nearly 80 million trades; Natixis and MUFG submitted incorrect data for about 150,000 trades and 650,000 trades, respectively, the SEC said.

These deficiencies were largely due to undetected coding errors, the SEC said, adding that the B-Ds' processes failed to validate the accuracy of its submissions.

The firms admitted to the findings in the SEC’s cease and desist orders and agreed to be censured, the SEC said, adding that Citadel agreed to pay $3.5 million in penalties, Natixis agreed to pay $1.25 million and MUFG agreed to pay $1.4 million.

"The SEC’s orders also found that Citadel, Natixis and MUFG willfully violated the broker-dealer books and records and reporting provisions," the SEC said.

“We routinely use blue sheet data to detect wrongdoing and protect Main Street investors through our enforcement efforts,” said Kelly Gibson, associate regional director of the SEC’s Philadelphia Regional Office. “Firms must be diligent and take seriously their obligations to provide accurate and complete data in response to our requests.”

Each of the firms has since addressed the deficiencies that led to the charges, including the use of an outside consultant and the adoption of policies and procedures for processing blue sheet requests, the SEC said.