We, the undersigned organizations concerned with data privacy and consumer protection, write to express grave concerns raised by the early reports of the significant data security breach affecting T-Mobile customers and applicants whose information was stored by Experian. Experian has admitted that the data breach included “names, addresses, Social Security Numbers and birth dates, as well as other information from 15 million T-Mobile customers and applicants.” Experian admits that the breach affected customers and applicants who applied for T-Mobile services or credit during a two year period, from September 2013 through September 2015.