On July 9, 2009, the Official Gazette of the Federation published the reforms and additions of several provisions to the Mexican Social Security Law (Decreto por el que se reforman diversas disposiciones de la Ley del Seguro Social), whereby Section VIII of Article 5-A, Sections XX and XXI of Article 304-A and Section IV of Article 304-B are reformed and paragraphs third, fourth, fifth, sixth, seventh and eighth which the current third becomes ninth of Article 15-A, paragraph second of Article 75 and Section XXII are added. The reforms and additions among other issues deal with the following: 1) The party that is considered and obligated to withhold or pay employer-employee social security fees and related fees established by the Social Security Law; 2) The information that contracting parties must provide to the Mexican Institute of the Social Security and 3) The infractions and penalties of non-compliance with the obligations of the employer.

The abovementioned decree is effect as of July 10, 2009.
For further reference please go to http://www.dof.gob.mx/nota_detalle.php?codigo=5098045&fecha=09/07/2009 to review the Spanish version of said decree.