T-Mobile US reported a better-than-expected quarterly profit and raised its forecast for customer additions for the year as heavy discounting helped attract subscribers.

Shares of the company, controlled by Deutsche Telekom, were up 3.5% at $48.40 in premarket trading on Monday.

The company said it now expected to add 3.7 million to 3.9 million branded postpaid customers on a net basis this year, compared with its previous forecast of 3.4 million to 3.8 million.

The Bellevue, Wash.-based company added 969,000 postpaid customers in the third quarter ended Sept. 30, up from 890,000 in the second quarter.

T-Mobile tmus and Sprint s , have been grabbing market share by gaining subscribers from bigger rivals AT&T and Verizon Communications.

AT&T t , which has proposed to buy Time Warner twx for $85.4 billion, lost 268,000 wireless phone postpaid customers in its third quarter.

Verizon vz added postpaid subscribers significantly below analysts’ estimate for the third quarter.

T-Mobile said it benefited from the launch of the iPhone 7 in the quarter and an increase in branded prepaid customer migrations to postpaid plans.

 

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However, churn, or the rate at which users switch to other networks, increased to 1.32% from 1.27% in the prior quarter.

On an adjusted basis, the company earned 27 cents per share, according to Thomson Reuters tri calculation, beating the average analyst estimate of 22 cents per share.

T-Mobile’s net income rose to $366 million, or 42 cents per share, in the third quarter from $138 million, or 15 cents per share, a year earlier.

Net income in the quarter included after-tax spectrum gains of $122 million.

Total revenue rose 17.8% to $9.2 billion.

Up to Friday’s close, the stock had risen nearly 20% this year.