America Movil (AMXL) SAB, the wireless carrier controlled by billionaire Carlos Slim, offered to cut fees to rivals and provide customers calls to other networks for no additional charge to convince Mexico’s antitrust commission to overturn a $1 billion fine.

Mexico’s largest phone carrier said today in a filing that it proposed the concessions in March during the antitrust agency’s review of the fine. The penalty was assessed a year ago for monopolistic practices in the market for fees charged to rivals.

The antitrust agency is scheduled to vote today on whether to uphold, overturn or reduce the fine. If it maintains the penalty, America Movil will seek an injunction, it said in the filing to the U.S. Securities and Exchange Commission. It’s “not probable” that the company will end up having to pay the fine, it said.

Under Mexican law, the antitrust agency must notify the parties involved in the case before it can announce the result of today’s vote.

America Movil’s proposal included reducing the interconnection fees it charges to rivals to 31 centavos (2.4 cents) a minute in 2014 from 39 centavos last year. It committed to providing plans with some minutes to call any mobile network at the same rate, and pledged to allow the antitrust agency to access information to verify it was complying with the concessions.

To contact the reporter on this story: Crayton Harrison in Mexico City at tharrison5@bloomberg.net

To contact the editor responsible for this story: Nick Turner at nturner7@bloomberg.net