From 1994 to 1998, Simon was the Executive Chairman of the Deutsche Bank Group in Asia. He then established his own company, General Enterprise Management Services Ltd (GEMS), a mid-sized investment group operating across Asia. In addition to this Simon was a founder of Distacom which made a number of mobile telecoms investments including Madacom in Madagascar, Spice Telecom in India and Sunday Communications in Hong Kong. He has also invested in other mobile operations in New Zealand, San Marino, Papua New Guinea and elsewhere.