EU antitrust regulators vetoed the proposed 29-billion-euro merger of Deutsche Boerse and the London Stock Exchange on Thursday, derailing the companies' latest attempt to create Europe's biggest stock exchange.

The European Commission said the fifth attempt, three public and two informal, by the companies to merge would have created a de facto monopoly in the markets for clearing fixed income instruments.

The EU antitrust enforcer said the exchanges did not offer sufficient concessions to allay its concerns.

Read more at Reuters.