Morgan Stanley employees using messaging platforms such as WhatsApp for official business-related communications have been hit with financial penalties from the investment management and financial services company, according to a report in the Financial Times on Thursday.

The penalties ranged from between a few thousand dollars up to $1 million for each employee, and were calculated based upon specific factors such as the number of messages sent, seniority, whether they had been warned previously to cease usage of the apps, and other factors, according to sources who had been briefed on the matter.

Morgan Stanley did not immediately respond to the report.

The firm had already agreed to pay the US Securities and Exchange Commission (SEC) $200 million in 2021 to resolve investigations into employee messaging on the communications applications which had not been approved by the firm.

Securities and Exchange Commission rules, as well as the rules of Wall Street’s self-regulatory body, the Financial Industries Regulatory Authority, require all broker-dealers to maintain clear records of all business related communications. The SEC has been investigating recently how well the industry has been maintaining its employee’s digital communications.

Morgan Stanley previously fired two top executives after discovering they had used WhatsApp to discuss official company business, and not maintained detailed records of the communications.