Citigroup is assembling major Wall Street banks for an initial public offering of Mexico's Grupo Financiero Banamex that could raise more than $3 billion. Citigroup is expected to lead the transaction, with Bank of America, Goldman Sachs and JPMorgan Chase also involved. The banks and Banamex are targeting a January listing, although the plans remain under discussion and could change. Citigroup is assessing whether to sell part of its remaining stake before the IPO, while smaller sales could occur in advance. The offering is part of Chief Executive Jane Fraser's broader retreat from consumer banking in several international markets. Citigroup sold 25% of Banamex to Mexican billionaire Fernando Chico Pardo last year and another 24% to investors including General Atlantic and Blackstone, leaving it with about 51%. Chief Financial Officer Gonzalo Luchetti said earlier this month that Citigroup planned to reduce its holding below 50% before listing the Mexican lender. Banamex appointed Edgardo del Rincon, the former head of Banco del Bajio, as chief executive earlier this year.