The Office of Fair Trading (OFT) is to investigate the acquisition of online spare parts retailer e-Spares by Connect Distribution Services.
Connect, which acquired the business last month in a deal thought to value e-Spares at £4m, runs spare parts sites for many retailers including B&Q.
The OFT is to explore whether the merger warrants a Competition Commission investigation, according to The Independent on Sunday.
A decision will be reached by September 26.
E-Spares sells spare parts for electrical appliances.