Wall Street ‘Sticker Shock’ WhatsApp Fines Were Years in Making

Record fines that the world’s biggest investment banks are expected to pay in the coming months reflect years of frustration among US regulators that their investigations were being hampered by unmonitored messaging among bankers.

Investigators at the Securities and Exchange Commission and Commodity Futures Trading Commission were repeatedly hindered by firms not archiving communications as required, according to people familiar with the matter. The watchdogs worried that missives on bankers’ personal phones about cutting deals, trading and courting clients were being completely lost and would ultimately make it harder to look for wrongdoing.

At the SEC, separate probes revealed a ...