Sprint shares fell 4.21 in early trade on Friday after S&P issued a report that affirmed its "BB" credit rating but said the company appeared to be losing customers to rivals such as AT&T Inc
Smaller carriers like Leap Wireless International Inc
"The ratings on Sprint Nextel continue to reflect a weak business profile because of its elevated churn relative to its peers, anemic subscriber trends, and significant competition from other wireless carriers, which is particularly important as the industry continues to show signs of maturation," it said.
Sprint's position as the third-largest U.S. wireless carrier and its strong portfolio of spectrum licenses were mitigating factors, it said.
(Reporting by Ritsuko Ando; Editing by Derek Caney)