(Corrects headline and lead to show that breach may have affected applicants, not subscribers)

Oct 1 (Reuters) - T-Mobile US Inc said about 15 million of its U.S. applicants may have been affected in a data breach at a unit of Experian Plc, a company that processes the telecom carrier's credit applications.

The hacked data included names, dates of birth, addresses, and Social Security numbers as well as additional information used in T-Mobile's own credit assessment. (http://t-mo.co/1M4FSSd)

Payment card or banking information was not acquired, T-Mobile Chief Executive John Legere said in a letter on Thursday.

(Reporting by Arathy S Nair in Bengaluru; Editing by Sriraj Kalluvila)