Disclosure of Equity Participation Pursuant to the Swiss Stock Exchange Act

Bad Ragaz / Switzerland - May 4, 2009 - INFICON Holding AG (SIX Swiss Exchange: IFCN), a leading, worldwide manufacturer of instrumentation and process control software for advanced industrial vacuum processes, today announced that Beat Frey owns as economic beneficiary through Corisol Holding AG, Grafenaustrasse 15, 6300 Zug, and KWE Beteiligungen AG, c/o Corisol Holding AG, Grafenaustrasse 15, 6300 Zug (contact person Beat Frey, +41 (0)41 760 3026) a total of 216,004 registered shares of INFICON Holding AG since a purchase on April 29, 2009. This represents 10.07% of the voting rights in INFICON Holding AG.