March 18 2011 Disclosure of Equity Participation Pursuant to the Swiss Stock Exchange Act

Bad Ragaz/Switzerland — March 18, 2011 — 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 according to a notification signed on March 15, 2011, Mrs. Ruth Wertheimer, Herzelia/Israel owns as economic beneficiary through 7-Industries Holding B.V., Claude Debussylaan 24, 1082 MD Amsterdam, The Netherlands (Contact: ANT Management B.V., Mr. R.C. Elshout Tel. +31 020 522 2555, Fax +31 020 522 2500) a total of 111,458 registered shares of INFICON Holding AG since a purchase on March 9, 2011. This represents 5.18% of the voting rights in INFICON Holding AG.