It comes after a lengthy regulatory approval process, with the Japanese investor originally touting a much larger figure of "up to $150 million".

The final investment buys Softbank a 7.5% stake in GBM via its subsidiaries, according to the securities filing.

The new funds will allow the more than 35-year-old company to "continue its investment strategy in technology, human capital and marketing," it added.

($1 = 20.0144 Mexican pesos)

(Reporting by Carolina Pulice, Editing by Isabel Woodford and Cynthia Osterman)