The CMA said that it had decided to refer the case for in-depth scrutiny because Diebold had failed to offer "satisfactory undertakings" to address its concerns. Both businesses supply cashpoints to banks. Earlier this month the regulator said it was worried that the deal "could lead to a substantial lessening of competition in the supply of customer-operated ATMs in the UK".
"A decision on the merger will be made by a group of independent panel members supported by a case team of CMA staff," the CMA said in a statement. "The deadline for the final report is 13 February 2017."
The CMA has already conducted an initial investigation into the proposed merger. It previously said it was concerned that the deal would leave "only one other credible competitor supplying such ATMs in the UK", and that there was just a "limited prospect" of new competitors entering the market.
The Diebold/Wincor transaction has already received regulatory clearance in other countries. However, the CMA has said that "the competitive situation in the UK could differ from other countries, for example in relation to the number of providers and the barriers facing other companies trying to enter the market".