(This article originally appeared on Bloomberg)

 

Banks are reducing trading in their dark pools, anticipating a surge in volume after Britain’s vote to leave the European Union.

Deutsche Bank AG temporarily shut off outside market makers in its dark pool, SuperX, according to people familiar with the matter. The bank told outside market makers that they would be prohibited from trading in SuperX on Friday, until the bank notified them it was ready to resume. Large institutional orders can still be matched in the pool.

Bank of America Corp. asked some outside trading firms to cut their messaging volume by half, said the people, who asked not to be named because the announcements were not public.

The measures come as U.S. markets brace for a wild trading day on the heels of the British vote. Morgan Stanley’s dark pool, also known as a broker-crossing network, wentoffline for a period in London earlier Friday. The pool has since gotten back up and running.