Wal-Mart is reportedly in talks to buy an 80 percent stake in Turkish retailer Migros Ticaret from London-based private equity group BC Partners as the retail giant is aggressively bidding for its expansion options in emerging markets.

The deal is expected to value Migros, which is Turkey's biggest retailer by sales, at more than $4bn (£2.5bn, €3.1bn) including debt, the Financial Times reported, citing "several people with knowledge of the discussions."

With its origin dating back to 1950s, Istanbul-listed Migros has 888 outlets including supermarkets, hypermarkets and discount stores across Turkey. The company employs about 15,000 people and operates stores in Azerbaijan, Kazakhstan, Macedonia and Kyrgyzstan.

The supermarket group operates under the Migros, Tansas and Macrocenter banners. Hypermarkets are operated as 5M, while discount stores are operated under the Sok banner.

Wal-Mart held meetings with Migros managers in recent days in Turkey but it is yet to place a formal bid for the Turkish retailer, FT sources said.

BC Partners acquired a 51 percent stake in Migros in 2008 and subsequently increased its interest in the retailer to 98 percent. In 2011, BC Partners sold part of its stake in the market.

The private equity group is in talks with other retailers and has received several expressions of interest for the remaining stake in Migros, according to the sources, who noted that French supermarket group Carrefour and UK retailer Tesco were also interested in buying the stake.

In its pursuit of an aggressive expansion in emerging markets, Wal-Mart has been facing troubles in connection with allegations of bribery in Mexico and India. Subsequently, the company conducted an internal inquiry into its operations in Brazil, China and India and slowed down new store openings there.

India's government recently launched a formal probe into a report by the company which said it had spent about $25m to influence US lawmakers to push its expansion into foreign markets.