In his new role, Back will help support Tiger AM's growth as an institutional investment advisory firm within Europe, Tiger AM said in a statement.
Based in Pfaeffikon, Tiger AM was founded in 2008 and manages around $100 million. It specialises in an absolute return strategy focused on listed equities primarily in Germany, Austria and Switzerland.
Back was previously CEO of Royal Mail from 2018 before standing down in May 2020 after a stint marked by battles with unions over a proposed restructuring plan for the UK postal monopoly.
Prior to taking the helm, he had founded and ran Royal Mail's German arm GLS for almost three decades.
Tiger AM founder Matthias Rutsch said: "I am sure his support and extensive network across the European business community will prove invaluable as we embark on the next stage of our growth."
(Reporting by Simon Jessop; editing by Carolyn Cohn)