Recent Developments at the CMA: 2017–2018


We describe three interesting cases that the UK Competition and Markets Authority (CMA) has dealt with over the past year: first, we discuss the merger of two online food ordering platforms—Just Eat and Hungryhouse—which required an assessment of competition in the presence of indirect network effects. Second, we discuss the vertical merger of a grocery retailer and wholesaler—Tesco and Booker—which posed the challenge of how to assess a firm’s incentives to foreclose its rivals when there are thousands of local markets. Finally, we discuss Open Banking, which lies at the heart of the package of remedies that came out of the CMA’s market investigation into personal banking, and sought to tackle issues of low customer engagement.

This is a preview of subscription content, log in to check access.


  1. 1.

    For a full description of the CMA’s duties, see its website at

  2. 2.

    See CMA (2017a).

  3. 3.

    The CMA looked at different measures of multi-homing of consumers, using survey evidence of searches on both platforms for the consumer’s last order, the Parties’ data on consumers using both platforms in the previous 6 months, and comScore data on cross-visiting of the Parties’ websites and apps. The estimated levels of multi-homing were similar for all these different definitions and datasets.

  4. 4.

    Economic theory also provided arguments in support of the CMA’s conclusion, given the high degree of multi-homing by restaurants between the Parties and the moderate strength of indirect network effects, see Sun and Tze (2007).

  5. 5.

    A rigorous econometric analysis would require estimating the two equations for Just Eat and Hungryhouse simultaneously, as the error terms are likely to be correlated. However, in all our cases, we face a trade-off between tractability and precision. In the institutional environment that we work in, there are clear benefits to using simple models, given the limited time and resources available. Based on these considerations, and following the standard practice in CMA cases, we have estimated the two equations separately.

  6. 6.

    See CMA (2017c).

  7. 7.

    Tesco was already largely vertically integrated into wholesaling pre-merger, sourcing most of its wholesale needs directly from producers; therefore the merged firm was unlikely to have an ability to foreclose competing wholesalers.

  8. 8.

    The CMA also considered theories of harm that are related to the exercise of buyer power by the merging firms, as well as standard horizontal theories of harm for a small number of areas where the Parties were direct competitors; this article focuses on the CMA’s assessment of local vertical foreclosure theories of harm.

  9. 9.

    Cases where the CMA used the GUPPI methodology include Shell/Rontec, Saint-Gobain/Build Center, Edmundson/Electric Center, Rexel/Wilts, Cineworld/City Screen, and Original Bowling/Bowlplex.

  10. 10.

    See for instance the CMA Retail Mergers Commentary, CMA (2017b), and page 21 of the US Horizontal Merger Guidelines, DOJ and FTC (2010).

  11. 11.

    This is a ‘weighted share of shops’ approach’; full details are provided in Appendix C of the Tesco/Booker final report

  12. 12.

    Specifically, a vGUPPI of 5% means that the merged firm would have the same incentive to raise the input price to the targeted downstream rival as the upstream merging firm would have pre-merger if its marginal cost of supplying inputs to that firm increased by an amount equal to 5% of the input price. Translating this upward pricing pressure index into a corresponding increase in the input price requires information about the cost pass-through rate of the upstream merging firm. For a more detailed discussion of the interpretation of pricing pressure measures see Farrell and Shapiro (2010).

  13. 13.

    See CMA (2018).

  14. 14.

    The CMA’s investigation covered both competition for personal current accounts (PCAs) and banking services to small and medium-size enterprises (SMEs). For brevity, this article focuses on PCAs.

  15. 15.

    CMA (2016).

  16. 16.

    This work drew on the review of the literature on biases and consumer behaviour in retail financial markets provided by Erta et al. (2013), including in particular Madrian and Shea (2001).

  17. 17.

    FinTech firms could access transaction data only if customers shared their online banking credentials.

  18. 18.

    The Second Payment Services Directive.

  19. 19.

    For example, in Canada, Mexico, Australia, New Zealand, Japan, Singapore, Israel, and Kenya.


  1. Competition and Markets Authority. (2016). Retail banking market investigation: Final report. Retrieved October 10, 2018 from

  2. Competition and Markets Authority. (2017a). Just Eat and Hungryhouse: A report on the anticipated acquisition by JUST EAT plc of Hungryhouse Holdings Limited. Retrieved October 10, 2018 from

  3. Competition and Markets Authority. (2017b). Retail mergers commentary. Retrieved October 10, 2018 from

  4. Competition and Markets Authority. (2017c). Tesco and Booker: A report on the anticipated acquisition by Tesco PLC of Booker Group plc. Retrieved October 10, 2018 from

  5. Competition and Markets Authority. (2018). Anticipated acquisition by Co-operative Group Ltd of Nisa Retail Ltd: Decision on relevant merger situation and substantial lessening of competition. Retrieved October 10, 2018 from

  6. Erta, K., Hunt, S., Iscenko, Z., & Brambley, W. (2013). Applying behavioural economics at the Financial Conduct Authority. FCA Occasional Paper No. 1. Retrieved October 10, 2018 from

  7. Farrell, J., & Shapiro, C. (2010). Antitrust evaluation of horizontal mergers: An economic alternative to market definition. The B.E. Journal of Theoretical Economics: Policies and Perspectives, 10(1), Article 9.

  8. Madrian, B., & Shea, D. F. (2001). The power of suggestion: Inertia in 401(k) participation and savings behavior. Quarterly Journal of Economics, 116(4), 1149–1187.

    Article  Google Scholar 

  9. Moresi, S., & Salop, C. (2013). vGUPPI: Scoring unilateral pricing incentives in vertical mergers. Antitrust Law Journal, 79(1), 185–214.

    Google Scholar 

  10. Sun, M., & Tse, E. (2007). When does the winner take all in two-sided markets? Review of Network Economics, 5(1), 16–40.

    Google Scholar 

  11. U.S. Department of Justice & Federal Trade Commission. (2010). Horizontal merger guidelines.

Download references


The views that are expressed in this article are those of the authors and do not necessarily reflect those of the CMA. We thank Siobhan Dennehy, Chris Doyle, Bill Roberts, Robert Ryan, and Tom Smith for helpful comments.

Author information



Corresponding author

Correspondence to Adriano Basso.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Basso, A., Bon, J., Tasker, B. et al. Recent Developments at the CMA: 2017–2018. Rev Ind Organ 53, 615–635 (2018).

Download citation


  • CMA
  • Competition policy
  • Mergers
  • Platforms
  • Remedies