Doubts hang over the planned tie-up of Deutsche Börse and NYSE Euronext after the exchange operators failed to offer enough concessions to assuage European Union antitrust concerns at a meeting on Wednesday, a person familiar with the matter told Dow Jones Newswires on Thursday.

The meeting, the last before the commission's holiday break, was with the commission's case team and aimed at presenting the response of competitors to the latest concessions made by the merger partners, said a second person close to the discussions, adding that no decision was taken.