UBS has joined Citi and Barclays in its ban on multi-dealer chat rooms (Reuters)

UBS has banned multi-bank and multi-dealer chat rooms as part of an internal review, becoming the latest big institution to do so in the wake of a number of regulatory probes.

A UBS spokesman confirmed the ban, but would not comment. It was revealed in a leaked internal memo reported by the Wall Street Journal.

"Staff are reminded that the communication tools provided to them by UBS are strictly for business purposes only," it said. "Personal devices must not be used to conduct UBS business at any time."

As well as multi-bank dealer chat rooms - which can be used upon explicit approval by senior staff - social chat rooms were also banned. Other banks to have banned such chat rooms include Citi and Barclays.

The Swiss banking giant's move comes as global regulators probe the currency markets on fixing concerns and demand banks hand over instant messages sent between traders. RBS handed over instant messages to the UK's Financial Conduct Authority (FCA) in October.

At the height of the Libor manipulation scandal, Barclays faced embarrassment when internal communications were published by the FCA as part of its damning evidence against the bank, which it fined £59.5m.

A Barclays trader emailed a Libor submitter: "If it's not too late low 1m and 3m [rate] would be nice, but please feel free to say 'no'...Coffees will be coming your way either way, just to say thank you for your help in the past few weeks". His friendly submitter responded: "Done...for you big boy."

"Dude. I owe you big time!" wrote another trader to a submitter. "Come over one day after work and I'm opening a bottle of Bollinger."