White & Case partners have voted overwhelmingly in favour of merging with German firm Feddersen Laule Ewerwahn Scherzberg Finkelnburg Clemm - marking the first major assault on the German market by a US firm since Shearman & Sterling moved in in the early 1990s.
As a result of the move, White & Case will rank among the world's biggest firms with more than 1,300 lawyers in 37 offices in 26 countries. It represents the first major merger between a US and German firm.
The merger will take effect on 1 July - a month before the Freshfields-Bruckhaus link-up.
Berlin, Hamburg and Frankfurt-based Feddersens has 80 partners and a further 96 lawyers in offices in Germany, Belgium and central Eastern Europe.
Managing partner Dr Cornelius Fischer-Zernin says the firm intends to continue employing mostly German lawyers in the offices in Frankfurt, Berlin and Hamburg and insists that it will not lose its own identity.
He says: "When we heard the result we jumped for joy, but now we have a lot of new challenges to face.
"Our vision is to maintain our independence and to continue our legal work for our German clients. We don't expect to change the way in which we did everything in the past."
"We want White & Case Feddersen to have the image of a German firm but with all the shared best practices of a fully-integrated partnership."
As a condition of the deal, the German firm will keep part of its own title and become known as White & Case Feddersens in Germany, the Czech Republic and Slovakia for the next five years.
But two weeks ago, five partners and three associates left the Frankfurt office to set up their own niche practice, led by the firm's former anti-trust team head Dr Josef Schulte.
Other departures include that of M&A expert Geza Toth to Weil Gotshal & Manges' London branch two months ago and environmental and administrative law specialist, partner Martin Diekmann, who will leave in July to join Esche Schümann Commichau in Hamburg.
"There are a number of reasons for this," says Fischer-Zernin. "We wish those who have left because of merger talks well. But at the same time we don't regret it because if you have partners who do not support the move it can be more detrimental rather than the other way round."
He expects the merger to bring in more M&A, banking and capital finance work.