Credit raters are monitoring Contel and Comsat.

Standard & Poor’s placed the debt ratings of Contel and Communications Satellite Corp. on its Creditwatch list with “developing” implications, meaning that ratings could be either raised or lowered. Moody’s Investors Service, meanwhile, said the merger agreement between the two telecommunications firms could have negative implications for Comsat debt issues, but did not put Comsat’s ratings under formal review. Both rating services said they would continue to monitor the progress of the merger plan.