MONTERREY, Mexico & NEW YORK--(BUSINESS WIRE)--Fitch Ratings has assigned the following ratings to Operadora de Sites Mexicanos, S.A. de C.V. (Opsimex): -- Long Term Local Currency IDR at 'BBB-'; -- Long Term Foreign Currency IDR at 'BBB-'; -- National Scale Long Term Rating at 'AA(mex)'; The Rating Outlook is Stable. The ratings are supported by Opsimex' significant operational scale within Mexico, provided by its large tower portfolio which provides critical passive infrastructure to America