The London Stock Exchange Group said its almost £21 billion planned merger with German peer Deutsche Boerse could result in 1,250 job cuts across the combined group.
The deal should eventually lead to €250m in revenue synergies a year.
LSE, which agreed in March to merge with Deutsche Boerse to create a giant European trading house, said it expects to achieve those synergies in the fifth year after completion of the deal.
It said that while there will be job cuts, 200 new roles could also be created because of growth initiatives.
LSE's shareholders will be asked to approve the merger on July 4, the company said.
Britons will vote on June 23 on whether to remain in the 28-member EU, a choice with far-reaching consequences for politics, the economy, defence and diplomacy in Britain and far beyond.
