Rangers under investigation for 'suspected anti-competitive behaviour' relating to replica kits
On Wednesday, the Competition and Markets Authority (CMA) confirmed it has opened an initial inquiry into potential "anti-competitive behaviour".
The investigation process, which is expected to take six months, will look into suspected breaches of competition law, it said.
The regulator said: "At this stage the CMA believes that it has reasonable grounds to suspect one or more breaches of competition law.
"The CMA has not reached a view as to whether there is sufficient evidence of an infringement of competition law for it to issue a statement of objections or, ultimately, an infringement decision, to any party under investigation."
It stressed that not all investigations lead to objections or an infringement decision by the CMA.
A spokesman for JD Sports said: "We are co-operating fully with the investigation and are unable to comment further at this time."
It is the latest investigation into JD Sports by the CMA, coming just weeks after the watchdog's decision to block the company's £90 million acquisition of rival Footasylum was reversed by the Competition Appeal Tribunal.
Rangers, who are in Betfred Cup quarter-final action at St Mirren tonight (8pm kick-off), were reported to have received almost £2.5million in unpaid replica shirt sales from Hummel and their brand partner back in January.