Four former Citigroup currency traders are suing the bank for unfair dismissal after they were let go amid a global probe into foreign-exchange rate rigging.

Carly McWilliams, Perry Stimpson, David Madaras and Robert Hoodless have all filed claims in a London employment tribunal, according to the court. The group have hearings scheduled between August and November, a court spokeswoman said.

At least 30 traders at a number of banks have been fired, suspended or put on leave in the last two years after it emerged the world's biggest lenders had attempted to collude to rig currency benchmarks. Banks have paid out more than $10 billion in fines over the scandal, with criminal investigations in the U.S. and the U.K. still active.

The currency probe came shortly after the industry was rocked by another rate rigging scandal, which also saw traders sue their employers for firing them without due course. At least two former Royal Bank of Scotland Group traders settled employment tribunal lawsuits in London.

A spokesman for Citigroup in London declined to comment. The Financial Times was first to report the lawsuits.

Lawyers for Madaras and Hoodless didn't immediately respond to requests for comment by phone and e-mail. No lawyers for McWilliams and Stimpson were listed on the court docket, according to a court clerk.

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