Parallel trade, price discrimination, investment and price caps Stefan Szymanski (Imperial College London) 1 and Tommaso M. Valletti (Imperial College London and CEPR) 2 March 2005 1 Tanaka Business School, Imperial College London, London SW7 2AZ, UK. Tel. +44-20-7594 9107, fax +44-20-7823 7685, e-mail szy@imperial.ac.uk . 2 Tanaka Business School, Imperial College London, London SW7 2AZ, UK. Tel. +44-20-7594 9215, fax +44-20-7823 7685, e-mail t.valletti@imperial.ac.uk , http://www.imperial.ac.uk/people/t.valletti