The bid amounts for the unit, known too as Banamex, were not disclosed by the sources.
The sources also cautioned that no deal was guaranteed with any party and Citigroup could ultimately decide to sell Banamex shares on the Mexican Stock Exchange instead.
Inbursa and Grupo Mexico declined to comment.
Backed by Slim, Mexico's richest person, Inbursa was flagged as a strong contender when Citigroup put Banamex up for sale in January.
However, mining tycoon Larrea has the firepower to compete as a candidate to buy Banamex, the sources said.