Firms being investigated include Carlyle Group, Apollo Global Management, KKR & Co., TPG, Blackstone, and hedge fund companies including Citadel, Reuters wrote. Senior executives are among the employees whose messages were reportedly collected.

“The executives gave their personal phones and other devices to their employers or lawyers to be copied, and messages discussing business have been handed to the SEC, three people said,” according to Reuters.

The SEC is apparently collecting more messages in this probe of investment advisers than it did in previous probes targeting broker-dealers. In the earlier broker-dealer investigations, “the SEC asked companies to review staff messages and report to the agency how many discussed work,” Reuters wrote. “SEC staff reviewed only a sample of messages themselves, according to three sources with knowledge of the previous investigations.”

The SEC declined to comment when contacted by Ars today. The government has been investigating how Wall Street firms keep track of employee communications for about two years, and the probes have already resulted in over $2 billion in fines for recordkeeping failures and use of unapproved communication methods.

As Reuters noted, the use of private messaging services that aren’t monitored by employers “has dogged Wall Street compliance departments for years. Because companies do not surveil personal messaging channels, using them to discuss business puts SEC-regulated employers in breach of requirements to record all business communications.”

Investment advisory firms have criticized the SEC demands, “arguing their recordkeeping requirements are narrower than broker-dealers’,” Reuters wrote. The Managed Funds Association industry group was quoted as saying that “unilaterally expanding the rules by enforcement actions sidesteps due process and creates a dangerous precedent.”

On August 8, the SEC said it charged 11 Wall Street firms with “widespread recordkeeping failures” related to the use of messaging platforms on personal devices. The firms “acknowledged that their conduct violated recordkeeping provisions of the federal securities laws” and “agreed to pay combined penalties of $289 million,” the SEC said.

“Today’s actions stem from our continuing sweep to ensure that regulated entities, including broker-dealers and investment advisers, comply with their recordkeeping requirements, which are essential for us to monitor and enforce compliance with the federal securities laws,” SEC Deputy Director of Enforcement Sanjay Wadhwa said at the time.