On 16 September the OFT and Competition Commission published the new joint Merger Assessment Guidelines. This is the first time the OFT and Competition Commission have published a joint set of guidelines.

The publication is a consolidation of previous guidelines under the Enterprise Act 2002 from both Authorities and aims to provide greater clarity on how the competitive elements of a merger are assessed. The guidelines set out the questions the Authorities will consider when reviewing a merger and contains information on what constitutes a "relevant merger situation" and a "substantial lessening of competition". In particular, the guidelines provide revised information regarding the "theories of harm" that will be considered when assessing a merger, the shift in emphasis away from market definition and towards a direct assessment of effects on competition and more detail on certain areas of merger analysis (including the counterfactual, barriers to entry, non-horizontal effects and efficiencies).