Citigroup Inc., continuing its round-the-world shopping spree, has dropped $12.5 billion in Mexico.

In what will be the biggest acquisition in Mexican history, the U.S.-based leader in financial services will acquire Grupo Financiero Banamex-Accival SA, familiarly known as “Banacci.” The deal will be the largest purchase Citigroup has made on its recent international buying binge. In the past year, Citigroup has snatched up credit card companies, a retail bank, and a financial services group in the U.K., Canada, Japan, and Taiwan.