This report, prepared for the Office of Fair Trading, examines potential reasons for the use of commission rates to pay for the services of, for example, estate agents, recruitment agencies or on-line auction providers. It considers whether such arrangements are likely to benefit customers, and how they might affect, and be affected by competition. It is based on a combination of theoretical analysis and a review of five sectors in which commission rates are commonly used, namely estate agency, financial service advisory, private client stockbrokerage, on-line auctions and temporary and contract employment. The main report can be downloaded here. The annex summarising the case studies is available here. Both documents can also be downloaded from the OFT website.