GameStop is selling its AT&T wireless stores for $700 million to Prime Communications, making the Sugar Land-based company the largest AT&T authorized dealer in the U.S.

The deal is expected to close by year-end and ends a multiple-year relationship between Grapevine-based GameStop and Dallas-based AT&T.

GameStop said it will use the money to pay debt, buy back shares and invest in its core video game and collectibles business. Its ThinkGeek brand sells apparel, gadgets and collectibles aimed at gamers.

The video game retailer said in June that it was considering options, including the sale of the company, and that effort is continuing, said Dan DeMatteo, GameStop's executive chairman.

The sale will allow GameStop to "enhance our performance with an increased focus on the video game industry and the rapidly growing collectibles space," DeMatteo said in a statement.

GameStop's mobile division, called Spring Mobile, owns 1,289 AT&T wireless stores. The stores were part of GameStop's strategy to use its real estate expertise and diversify from its main video game business. GameStop built up the business, mostly through acquisitions, into the largest AT&T store operator.

Terms of its dealer agreement with AT&T changed in 2017, and the wireless stores were no longer as lucrative for GameStop. In September, interim CEO Shane Kim said the contract was relaxed some in GameStop's favor.

The sale to Prime Communications does not include Simply Mac stores, said Joey Mooring, GameStop spokesman. Simply Mac is a chain of authorized Apple retailers mostly located in smaller and suburban markets. In January, GameStop sold another group of AT&T stores that operated under the Cricket Wireless brand.

Prime Communications started business in 1999 and owns 600 AT&T stores in 22 states, according to its website. It owns several stores in Dallas-Fort Worth.

It's been a tough year for GameStop, starting with the death in March of longtime CEO Paul Raines. Michael Mauler, another veteran executive who replaced Raines, resigned in May for "personal reasons." He had only been in the CEO job since February, when two other longtime executives were fired.

Twitter: @MariaHalkias