Coles Group Ltd (COL.AU) saw its shares plummet 5.09% during intraday trading on Wednesday following regulatory opposition to its expansion plans in Western Australia.

The Australian Competition and Consumer Commission (ACCC) announced it opposes Coles' proposed acquisition of a leasehold for a new supermarket and liquor site in the Kalgoorlie-Boulder area. The regulator stated the deal would "materially harm competition in the retail groceries space" and likely "lead to the exit of an effective independent full-line competitor" in the region.

Coles disclosed the acquisition of the leasehold interest in November 2025 with plans to open a large format supermarket and a Liquorland store at the currently vacant site. A Coles spokesperson expressed disagreement with the ACCC's decision, stating that blocking the development "does not promote competition" and denies shoppers greater choice and convenience.