Barclays, Citigroup, JPMorgan, Royal Bank of Scotland and UBS are facing a £1 billion ($1.23 billion) class action lawsuit over rigging the foreign exchange markets — one of the biggest cases of its kind in the UK.

It comes just months after European regulators hit many of the same banks with a €1 billion-plus penalty for manipulation of these same markets between 2007 and 2013.