This paper assesses the impact of the 2006 OFT intervention addressing the anti-competitive exchange of information in the setting of school fees by a group of 50 schools in the United Kingdom. Availing of a large panel dataset of school fees and other schools’ characteristics, the paper employs a differences-in-differences methodology to allow robust and statistically significant findings to be drawn. Evolution of school fees of the group of 50 infringing schools—subject to OFT treatment—is compared with a ‘no-intervention’ counterfactual scenario, informed by reference to a control group of 178 non-participating schools. The analysis controls for other factors that may influence the determination of fees, most notably the quality of the schools. The analysis finds the OFT intervention leads to a reduction of 1.6 % in the boarding fees of the infringing schools. This equates to savings of approximately £500 per boarder per term, and suggests consumer savings of around £85m may have been realised since intervention. Additional potential effects in spurring wider competitive responses by non-infringing schools are not considered in this analysis, and underline the conservative nature of the findings.