The London Stock Exchange's in-house team, led by Allan Cameron, played a key role in negotiating its strategic alliance with the Deutsche Borse.
Cameron, a member of the Stock Exchange's management committee, will now sit on a joint London-Frankfurt project board, with fellow management committee member Martin Wheatley, chief executive Gavin Casey and three members of the Borse's executive.
Cameron and his German counterparts now have a huge task ahead of them in harmonising the two markets.
The aim is to create the "nucleus of a single European stock market" by combining, initially, the trading of the top 300 German and UK stocks.
But the first step is only to encourage German companies listed on the London Stock Exchange to move to Frankfurt and UK companies on the Borse to move to London.
Since there are more German companies listed in London than UK companies listed in Frankfurt, and since both exchanges are taking an equal stake in the venture, national press commentators have called the deal a good bargain for the Deutsche Borse.
The secretly negotiated deal has also upset the Paris bourse, which had hoped to enter an alliance with the German exchange.