With workplaces increasingly dominated by instant messaging apps like Slack, global banks (and regulators) are taking unprecedented measures to manage employee communication.

Employees at HSBC are not allowed to text on their work phones, according to a person familiar with the matter. Bloomberg first reported the ban.

In August, the Securities and Exchange Commission (SEC) and the Commodity Futures Trading Commission (CFTC) fined 11 brokerage and investment firms $549 million for using messaging apps like WhatsApp.

Employees’ texts and other business communications must be stored and used in accordance with strict compliance rules.

However, WhatsApp and other instant messaging apps are particularly problematic since they connect to bankers’ personal devices and are difficult to monitor for recordkeeping purposes.

Since financial institutions fear more missteps and fines will follow, they are actively limiting how their employees communicate about official business.

“Banks use a variety of approved channels to communicate in compliance with regulatory requirements,” a spokesperson said. “HSBC reviews and adjusts its corporate devices as needed, like many other banks.”

HSBC’s text ban came just a few months after the London-based bank paid $75 million in penalties to the CFTC to settle what it deemed “manipulative and deceptive trading and recordkeeping failures.” For its misuse of WhatsApp, the British lender also paid $15 million to the SEC.

According to Reuters, the Carlyle Group and Blackstone are also under investigation for using WhatsApp and Signal for business purposes.

Over $2.5 billion has been paid to lenders such as Bank of America, Wells Fargo, and Citigroup for similar recordkeeping violations since last year.