Some of Wall Street’s biggest firms have been fined $1.8bn (£1.7bn) by US financial watchdogs after staff discussed deals and transactions on their devices and apps.
The Securities and Exchange Commission (SEC) says the investigation found “pervasive out-of-channel communications”.
Barclays, UBS and Goldman Sachs were among the 16 companies named by regulators.
The broad industry investigation is a landmark case for the SEC and the Commodity Futures Trading Commission (CFTC).
“Finance, ultimately, depends on trust. By failing to honour their recordkeeping and books-and-records obligations, the market participants we have charged today have failed to maintain that trust,” SEC chair Gary Gensler said.
From January 2018 through September 2021, bank workers routinely communicated about business matters with colleagues, clients and other third-party advisers using apps on their devices such as text messages and WhatsApp, regulators said.
The firms did not preserve most of those chats, which violated federal rules requiring broker-dealers and other financial institutions to keep business communications records.
That hampered the ability of regulators to ensure compliance with key rules and gather evidence in unrelated probes, the agencies said.
The investigation has shaken Wall Street, with some bankers losing their jobs. It has also forced companies to introduce strict new measures to stamp out the unauthorised use of apps.