JD Sports' £90 million deal to buy high street rival Footasylum is to face a full-scale probe by the competition watchdog after refusing to offer any solutions to ease concerns.
The Competition and Markets Authority (CMA) said it was set to refer the planned acquisition for a so-called phase two investigation, amid worries it could lead to higher prices and worse choice.
JD Sports declined to offer any solutions to address the CMA's concerns by the September 26 deadline, saying it "firmly believes that there is clear evidence that the acquisition would not result in a substantial lessening of competition".
Peter Cowgill, executive chairman of JD Sports Fashion, said: "The CMA has referred their review of this acquisition to phase two on the basis that it could be bad for competition and may have an impact on price. I strongly disagree with this.
"This transaction will not result in any price increases or a reduction in product ranges or service quality.
"The focus of all of our group businesses is to ensure we deliver a best in class, multi-channel experience to our consumers by offering a compelling product proposition."