The company will continue to use Congrex in its brand name and will merge the two companies to Congrex Switzerland Ltd before the end of 2013.
The agreement was signed yesterday and the acquisition will be completed in the next few days.
Congrex Switzerland is providing consultancy and management services in the areas of association and conference management including accommodation handling and flights.
The 40 staff members at Congrex Switzerland are based in its current premises in Basel.
Managing director Alain Pittet said: "Most of the management of Congrex Switzerland worked already for the well-known AKM, founded in 1982, which was bought in 2007 by the Congrex Group.
"Fortunately, the major part of our clients were already clients of AKM and have worked with our staff for many years. And exactly these clients encouraged us to offer for a management buy-out".
Congrex Switzerland works with over 25 Swiss and international associations, including the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) since 1999, the European Neurological Society since 1995 (ENS) and the European Stroke Conference (ESC) since 2003.
Congrex Switzerland is currently developing its new corporate identity and plans to launch its branding early next year.