Biggest bank in Mexico is Banamex, former Banco Nacional de Mexico (Mexican National Bank). Today Banamex is owned by Citigroup and some Mexican stocholders.
Other big banks down here are:
BBVA Bancomer (Mainly Spaniard Ownership).
Santander Serfin (Mainly Spaniard Ownership).
HSBC (British)
Banorte (Full mexican ownership).
Banorte
the coffee can in the hole in the backyard