Citigroup has sold 80% of its stake in Banamex to Mexican conglomerate Grupo Bal, owned by entrepreneur Alberto Baillères, for approximately $7.1 billion, according to a statement issued by the US bank on Thursday.

Citigroup, which had owned 100% of Banamex since 2001, will continue to hold a 20% stake in the Mexican bank, and the transaction is subject to regulatory and governmental approvals.

The sale of most of Banamex is part of Citigroup's strategy to simplify its business model and reduce its operations in international markets, especially those with low profitability.

Grupo Bal is a Mexican conglomerate owned by entrepreneur Alberto Baillères, who is also the owner of mining company Grupo Peñoles and insurer GNP. The acquisition of 80% of Banamex makes it one of the major players in the Mexican financial market.

The sale of Banamex comes after Citigroup has been strategically reviewing its businesses in recent years. The move comes after Citigroup CEO Jane Fraser announced plans to focus on the bank's most profitable businesses and simplify its business model.

Banamex is one of Mexico's largest banks, with over 1,500 branches throughout the country and a strong presence in the credit card and personal loan sectors. The sale of the majority of Banamex is expected to be completed in the coming months, subject to regulatory and governmental approvals.

The sale of Banamex also marks the end of an era for Citigroup, which had seen the Mexican bank as a key piece of its global strategy for decades. However, the sale of most of Banamex is a sign that the US bank is focused on reducing its international operations and focusing on markets where it can obtain greater benefits.