T-Mobile USA, the fourth-largest U.S. wireless carrier, says it lost subscribers in the second quarter as prepaying subscribers fled to other carriers. But T-Mobile has added crucial contract-signing customers.

It's a reversal of the trend for the carrier over the past year. It's lost contract subscribers since last year's second quarter, but kept adding prepaying ones.

T-Mobile said Thursday that it lost 93,000 customers, ending the quarter with 33.6 million.

T-Mobile is a unit of German phone company Deutsche Telekom AG.