Franklin Templeton Investment Management has upped its stake in Tennent's owner C&C Group to more than 6%.
A stock market notification yesterday showed Franklin purchased more than 3.4 million shares earlier this week.
That took its holding in Dublin-based C&C, which also owns cider brands such as Magners and Bulmers, to in excess of 20.96 million shares.
The exact price Franklin paid for the stock it bought this week was not revealed, but C&C's shares have been changing hands at around €4.50 (£3.70).
At that price the investment manager would have had to fork out more than €15 million (£12.4m) to snap up the additional shares.
Last month, C&C said total Tennent's volumes in the first nine months of its financial year had dipped by 4.7% with net revenue falling by 2.9%.
But the Caledonia Best ale along with Belgian beer brand Heverlee were both said to have continued to grow volumes in Scotland.
C&C has invested heavily in the Wellpark Brewery in Glasgow since buying Tennent's from Anheuser-Busch InBev for £180m in 2009.
Last year, it unveiled plans for a joint venture with Alloa-based Williams Bros to build a new craft brewery and brewing centre of excellence in the Drygate area of Glasgow, next to Wellpark.
Shares in C&C closed up 12 cents, or 2.55%, at €4.62.