The Competition and Markets Authority (CMA) has launched an in-depth (Phase 2) investigation into the merger of Sainsbury’s and Asda and has confirmed that its effect on fuel sales will be an issue it focuses on.

The move follows an initial investigation announced on August 23, when the CMA said the companies had requested a ‘fast-track’ referral to Phase 2.

In its latest statement the CMA said the Phase 1 investigation found, that the deal raises sufficient concerns to be referred for a more in-depth review.

It was concerned that the companies stores overlap in hundreds of local areas, meaning shoppers could face higher prices or a worse quality of service.

These concerns will be considered further in the Phase 2 investigation, along with other issues raised so far with the CMA – including those relating to fuel, general merchandise (such as clothing) and increased ‘buyer power’ over suppliers.

An issues statement, setting out in detail the issues that the inquiry group expects to investigate, will be published in the coming weeks. Members of the public and other interested groups will be invited to give their views on this.

Under the CMA’s rules the deadline for delivering its report will be 5 March next year.