(Reuters) -AT&T ( T ) added more wireless subscribers than expected in the third quarter on Wednesday, as bundled plans and heavy promotions around the latest iPhone launch helped it attract more customers in a fiercely competitive market.

Shares of the company were up 4% in premarket trading.

The quarter ended September is a critical period for U.S. wireless carriers, with competition peaking around Apple's annual iPhone launch.

Like all other carriers, AT&T ( T ) has also rolled out lucrative promotions for the iPhone 17 series to lock in new subscribers and encourage existing users to upgrade to pricier plans.

It added 405,000 monthly bill paying wireless subscribers, compared to expectations for 334,100 additions, according to FactSet.

By packaging wireless and fiber broadband services together for a discount, AT&T ( T ) has encouraged more customers to take multiple offerings and reduce customer exits. More than 41% of fiber households have also opted for mobile plans.

Investor focus has also been on the company's recent strategic moves to bolster its network capabilities. AT&T ( T ) recently announced a landmark $23 billion deal to acquire wireless spectrum licenses from EchoStar.

Equipment revenue in the third quarter grew 6.1%, pushed by stronger phone sales. Operating costs in the mobility unit rose 3.8%, driven by higher expenses from selling more and pricier phones and increased spending on marketing and promotions.

Revenue from its business wireline unit fell 7.8% in the quarter, hurt by declines in legacy voice and data services.

On an adjusted basis, AT&T ( T ) earned 54 cents per share, largely in line with estimates, according to LSEG data.

Total third-quarter revenue stood at $30.7 billion, missing estimates of $30.87 billion.

(Reporting by Harshita Mary Varghese in Bengaluru; Editing by Arun Koyyur)