A unit of Russian private financial company Alfa Group has increased its holding in Sun Interbrew. Alfa-Eco confirmed on Monday that it has increased its stake in the company to almost 16% and intends to buy more shares, leading to speculation the Russian investment firm is looking to acquire a blocking stake in the company.

Last week, Alfa-Eco said it had acquired 10.4% of the voting shares in the brewer.

According to TheDeal.com, a spokesman for Alfa-Eco, part of Russian entrepreneur Mikhail Fridman's Alfa Group, said the firm dipped into the open market for a second time last week to increase its stake to 15.8%. The spokesman said the company intends to raise this holding further.

With Indian financial investor Sun Group and Interbrew each hold 34.25% of the Class B voting stock, it would appear unlikely that Alfa-Eco believes it can acquire a majority stake in the company. The purchases come at around the same time, however, as the expiration of an agreement between Sun and Interbrew governing the disposal of their stakes, TheDeal.com notes.

Under a shareholder agreement, the two companies pledged not to transfer any voting shares before 15 June. Each partner has pre-emptive rights to buy the shares if one side decides to exit and has to extend the offer to minority shareholders at the same price.