Sweden’s Economic Crime Bureau has initiated a probe into a possible leak of information prior to the announcement of a joint bid from suitors Nasdaq and Borse Duabi.

“I can confirm that we have started an investigation,” the Bureau’s prosecutor, Robert Engstedt said. He revealed that the probe will centre on suspicious trading over two days which occurred just a day before the joint bid from Nasdaq was revealed on 20 September.

Before news of the joint bid broke, both Nasdaq and Borse Dubai were involved in a fierce battle for control of the Nordic exchange, with Nasdaq originally agreeing a deal for OMX in May only for the Dubai exchange to return with a higher offer on 17 August. Despite rumours that Nasdaq would return with a higher offer, Borse Dubai and Nasdaq instead returned with a joint bid, that would see Nasdaq control OMX while Borse Dubai will receive Nasdaq’s stake in London Stock Exchange and also a stake in Nasdaq.