Article 129 of the Mexican Immigration Law Regulation
The condition of visitor’s stay without permission to carry out remunerated activities, foreseen in article 52, section I, of the Law, may be authorized to the foreigner who demonstrates any of the following assumptions:
I. Have sufficient economic solvency to cover the amount of lodging and living expenses during their stay in the national territory, or
II. Have an invitation from an organization or a public or private institution established in the national territory to participate in any activity for which he/she does not receive income in the national territory. The organization or institution must prove financial solvency to cover the lodging and living expenses of the foreigner.
The foregoing, in accordance with the procedure and requirements set forth in the general administrative provisions to be published in the Official Gazette of the Federation.