Faced with the possibility of a no-deal Brexit or patchy UK access to the European Union's financial markets in future, London-based pan-European Cboe built a Dutch hub to ensure continuity for EU clients.
Volume in Amsterdam has been tiny. On Tuesday trading topped just 2,426 euros, rising to 1.23 million euros on Wednesday, and 3,648 euros so far on Thursday according to Cboe Global Markets data.
An industry veteran described it as "cleaning the pipes".
Cboe, which typically has the biggest daily market share with about 20% of European stocks, said customers were testing their access to the new platform.
"We expect initial volumes on Cboe NL will continue to be low as many firms may choose not to adjust their trading strategies until there is more clarity around the shape and timing of Brexit," a Cboe spokeswoman said.
Customers can still trade EU27 listed shares on Cboe in London if they want to.
Rivals London-based Aquis Exchange and London Stock Exchange's pan-European platform Turquoise have also built new EU hubs, but have not formally started trading.
Meanwhile, British and EU securities regulators remain at loggerheads over where EU27 shares can be traded in the event of a no-deal Brexit.
It is unclear if Britain and the EU will agree a divorce settlement by Brexit Day on Oct. 31. A deal would mean a business as usual transition period to the end of 2020.
But a crash out could see swathes of share trading moving from London to the three new hubs, denting the capital's standing as a global financial hub.
(Reporting by Huw Jones; Editing by Alexandra Hudson)
By Huw Jones