Deutsche Börse is expected to achieve shareholder support for its merger with NYSE Euronext on Thursday as the German exchange operator counts up shares tendered via mail, according to a person familiar with the matter.

By the close of business Wednesday Deutsche Börse had reported 60.16% of shares tendered in favour of the combination, with the offer set to formally expire at 22.00 GMT on Wednesday and 75% of shares needed to move ahead with the blockbuster deal agreed to in February.