Mexico is probing seven multinational companies…to investigate whether they avoided paying their taxes amid an international crackdown…Oscar Molina, who lead audits of big companies at Mexico's tax collection agency SAT, said the seven firms, which cannot be identified for legal reasons, include Fortune 500 companies in the automotive, mining and retail industries. The majority are U.S. firms and are part of a pool of 270 multinationals that the agency has flagged for possibly skirting their tax obligations by shifting profits to countries with lower taxes despite having a big presence in Mexico…The companies are cooperating with the probe and are providing information on their tax structures to the agency, he said….The move is part of a Group of 20 nations (G20) effort…[that] could help boost the tax take in Mexico, which has the weakest tax revenues in the 34-nation Organization for Economic Co-operation and Development (OECD), due to elusion, evasion and a small tax base.