Four banks - JPMorgan, Barclays, Citigroup and RBS - have agreed to plead guilty to US criminal charges.
The fifth, UBS, will plead guilty to rigging benchmark interest rates.
Barclays was fined the most, $2.4bn, as it did not join other banks in November to settle investigations by UK, US and Swiss regulators.
US Attorney General Loretta Lynch said that "almost every day" for five years from 2007, currency traders used a private electronic chat room to manipulate exchange rates.
Phil Beckett, partner at Proven Legal Technologies – the corporate forensic investigation and e-disclosure experts, comments on the latest news that five banks are to pay a total of £3.6bn worth of fines for forex rigging.
He says “The Forex scandal brings to life the real need for effective communications monitoring. Serious employee malpractice could have been captured by a more thorough analysis of communications in a proactive context. Intelligent analysis of company data and communications – such as chat messages – on a regular basis can provide early warnings of issues such as those uncovered in the Forex scandal.
“Until now, audits of company data have primarily been used posthumously as way of finding out “what went wrong”. However, prevention is always better than cure, and the financial services sector needs to get much better at using technology to spot problems before they occur if we are to avoid future crises – and penalties – such as these.”