The paper looks at agreements in the banking industry, comparing suggestions from economic theory with decisions by antitrust authorities in Italy and in Europe. I consider separately agreements on payment systems from other deals. In the first group, I distinguish between traditional and "innovative" payment services. In the second group, I analyse agreements devoted to the standardisation of contractual clauses and to information sharing schemes. Analysis of antitrust files shows a clear separation between deals that define economic conditions in a contractual relationship and those that do not. In particular, the antitrust authorities sanction agreements that fix economic provisions applicable to consumers, either directly or through an information sharing regime. On the contrary, economic theory seems to suggest that product differentiation related to the contractual terms that consumers deem to be more relevant is sufficient to relax price competition. However, product characteristics like banks' location or switching costs are never considered by antitrust authorities in their decisions and only price seems to matter.