Starting Jan. 25, AT&T’s 50 million Mobile Share Value customers will be able to rollover unused data to the following month, the company announced Wednesday.

The news comes a shortly after T-Mobile revealed ‘Data Stash,’ a feature that allows its customers to roll over unused high-speed data. The ‘stash’ can be used any time in the following 12 months.

Roll over for AT&T customers applies to both business and consumer accounts, but leftovers come with a one-month expiration date.

Although AT&T’s announcement came after T-Mobile’s, Ralph de la Vega, president and CEO of AT&T Mobility and Business Solutions, said he thinks its competitor took the company’s rollover concept.

“We had plans to roll it out here at CES [Consumer Electronics Show] for a long time. We trademarked the name ‘Rollover Data’ earlier in the year,” he told USA Today.

John Legere, CEO of T-Mobile, took to Twitter to respond to the news.

“Nothing but marketing BS – @att is still charging you overages (so they can pressure you to buy more data) and still confiscating your data!” he wrote on the social media network.

T-Mobile does not charge its users domestic overages on allotted data, although speeds slow down significantly once the amount of high-speed data is consumed.

Jackdaw Research analyst Jan Dawson noted key differences in rollover features offered by both carriers.

“AT&T’s version differs significantly from T-Mobile’s version. It’s less generous, with a single month of rollover than [12] months, but that should make it both easier for customers to keep track of and more manageable from a network load perspective,” Dawson said. “T-Mobile’s plan risks creating a situation similar to airline miles, where customers have a hard time keeping track of which miles (or Gigabytes of data) expire when.”

(With reports from CNN and USA Today)