Compiled By Deborah Austin The Private Exchange (PTX) market will surpass public and consortium exchange markets to become the cornerstone of B2B e-commerce, predicts AMR Research. AMR describes PTX as the application platform on which a company builds its online trading interface to suppliers and customers, providing a single integration point for its B2B and serving as repository for strategic applications enabling commerce with trading partners. The largest companies can expect to spend $50 million to $100 million building a PTX, while smaller companies likely will lease capability, says AMR. By 2005 the PTX market should reach $35 billion, with a 68% compound annual growth rate. Boston-based AMR provides research and analysis of e-business strategies/technologies.