Guillermo Cantú has been a partner of Santos Elizondo since 2005. His practice focuses mainly on corporate law, mergers and acquisitions, international business transactions and estate planning.

Guillermo represents Mexican and foreign companies in all types of industries. He has participated, among other transactions, advising Ally Financial, Inc. on the sale of Aba Seguros to Ace Limited and on the sale of Ally Credit, S.A. de C.V. and Servicios GMAC, S.A. de C.V. to General Motors Financial Company; Grupo Valores Operativos Monterrey, S.A.P.I. de C.V. in the sale of Primero Fianzas to Liberty Mutual, Primero Seguros to Amtrust Group and Primero Seguros Vida to Sura; to Masterlease (UK) Limited in the sale of Masterlease to Banregio; to the shareholders of Quimicompuestos in the sale to Univar; to the shareholders of Thermotek in the sale of such company to BASF; to Grupo Tredec in the sale of its assets to Finsa and Walton St. Capial; to Banregio in the sale of its assets to Finsa and Walton St. Capial; to Grupo Tredec in the sale of its assets to Banregio. He also participated in the purchase of three subsidiaries of Capita Corporation from Banregio; and a group of private investors in the purchase of a minority stake in the Ver de Verdad clinics.

Guillermo is ranked in "Band 1" in the corporate/commercial practice area in Mexico by Chambers & Partners.

Guillermo Cantú was a Foreign Associate at Davis Polk & Wardwell from 1993 to 1994, Latin American Legal Director of General Motors Acceptance Corporation in Detroit, Michigan, United States of America from 1999-2001 and International Legal Director of the same company from 2002-2005 in London, England.

In 1991, Guillermo Cantú Treviño obtained his law degree from the Instituto Tecnológico y de Estudios Superiores de Monterrey. Subsequently, he obtained a Master's Degree in International Law from the University of Illinois at Urbana-Champaign in 1993.