T-Mobile is currently the fourth-largest mobile provider in the U.S. With almost nothing to lose following the company’s failed acquisition by AT&T, the carrier began offering prices lower than its competitors. After naming John Legere CEO, T-Mobile took on its “un-carrier” branding and offered unlimited data as well as no contract subscription plans. Though these things weren’t quite enough to make T-Mobile a real competitor to AT&T and Verizon at the time, the company’s rapid 4G network rollout has now made it a real contender.

This week, market research firm Kantar Worldpanel ComTech released a new report showing that T-mobile’s share of U.S. smartphone sales rose over 1% during the three summer months ending in August. The mobile provider now represents 13.2% of U.S. smartphone sales. This brings it closer to Sprint’s 14.6% share, though it is still far from Verizon’s 37.1% share or AT&T’s 21.7% cut.

This increase comes after T-Mobile had seen its year-over-year market shares decline. Kantar stated that T-Mobile’s rise could be due to its strong iOS sales, as well as its new “Jump!” pricing scheme. “Jump!” allows customers to pay off their device costs over time and also enables them to upgrade those devices more frequently. Though the majority of smartphones sold by T-mobile are Android-based, the carrier’s top-selling smartphone this summer was the iPhone 5.

“When iOS first debuted on T-Mobile in mid-April, the majority of sales came from consumers upgrading from a featurephone to their first smartphone,” said Dominic Sunnebo, global strategic insight director at Kantar. “However, looking at those who purchased an iPhone in the August period, 56% of those consumers came from another smartphone, including 38.5% from an Android device.”