The Economist, The CAT and the (alleged) fiddle 

Banks are in the frame for Britain’s latest collective-action claim

THE LAUGHING stopped long ago. Between 2007 and 2013, in online chatrooms called “Three Way Banana Split”, “Essex Express ’n the Jimmy” and other rib-ticklers, currency traders yapped about all sorts of things—including market tactics. The banter has cost their employers dear. Banks have been fined over $10bn for market-rigging by American and European regulators, including €1.1bn ($1.2bn) by the European Commission in May. An American class action cost 15 banks $2.3bn. But a lawyer’s work is never done. On July 29th Scott+Scott, an American law firm, filed a collective-action case at the Competition Appeal Tribunal (CAT), an antitrust forum in London.

Cases like this are still a novelty in Britain, despite a theoretically helpful change in competition law in 2015. Collective claims may now be brought to the CAT on an “opt-out” basis, in which members of a specified class are included in the claim unless they choose not to be. If a monopolist rips off its customers, it may do lot of harm in total, but the damage to each may be small. Given the cost of going to court, many may not bother suing. But the easier a collective-action case is to bring, the likelier they are to gain redress.