A general view of London showing Tower Bridge, The Shard, London City Hall, The Fenchurch Building, also known as The Walkie Talkie, The Tower Of London, St. Paul's Cathedral, in London, Britain, March 23, 2022.  Picture taken with a drone.
A general view of London showing Tower Bridge, The Shard, London City Hall, The Fenchurch Building, also known as The Walkie Talkie, The Tower Of London, St. Paul's Cathedral, in London, Britain, March 23, 2022. Picture taken with a drone. Reuters / YANN TESSIER

A proposed multi-billion pound claim brought by thousands of asset managers, pension funds and financial institutions against major banks over alleged foreign exchange (forex) rigging has been blocked by a London court.

London's Competition Appeal Tribunal (CAT), which had been considering the case against JPMorgan, Citigroup, Barclays, UBS and NatWest since last July, ruled on Thursday the case was not suitable to proceed as a U.S.-style, opt-out class action.

The European Commission paved the way for the proposed lawsuit by fining banks more than 1 billion euros ($1.11 billion) in 2019 over two forex cartels, dubbed "Essex Express" and "Three Way Banana Split", between 2007 and 2013.

Michael O'Higgins, the former chairman of British watchdog The Pensions Regulator, and Phillip Evans, a former inquiry chair at the Competition Markets Authority, had been vying to lead a class action on behalf of financial claimants.

O'Higgins said his team was reviewing its options.

"This decision is extremely disappointing, because this claim is exactly the sort of claim that opt-out proceedings were introduced to facilitate in order to provide access to justice to all entities affected by the illegal behaviour of cartelists," he said.

"We are reviewing our options to decide how to move forward in a way that best serves the class that we seek to represent."

A representative for JPMorgan welcomed the news, saying the tribunal had "acknowledged the clear weaknesses in the applicants' cases". Others were not immediately available for comment.

($1 = 0.9021 euros)