Purchasing power parities (PPPs) are the rates of currency conversion that try to equalise the purchasing power of different currencies, by eliminating the differences in price levels between countries. The basket of goods and services priced is a sample of all those that are part of final...

This paper was prepared as a background note for a discussion held at the OECD in December 2015 on Across Platform Parity Agreements. It summarises the economic theory and case law as it relates to recent cases involving vertical agreements specifying horizontal price links.