The Office of Fair Trading (OFT) is to look at AB-InBev's sale of Tennent's lager to Magners producer C&C Group.
The £180m deal includes the Glasgow Wellpark Brewery in Scotland and the rights to Tennent’s Ales and assets located in Scotland, Northern Ireland and the Republic of Ireland, which currently belong to AB-InBev.
The deal is due to be completed by the end of the year.
The OFT said it would consider whether the deal would result in a "substantial lessening of competition within any market or markets in the United Kingdom for goods or services that warrants reference to the Competition Commission for investigation and report".
