Unlimited data plans have been a boon for the likes of T-Mobile US Inc. (TMUS) and Sprint Corporation (S), and even Verizon Communications Inc. (VZ) has gotten back into the game despite staying away from the plans for several years. The last holdout—AT&T Inc. (T)—caved late Thursday, offering its own version.

Late Thursday, AT&T announced an unlimited data plan for all of its postpaid customers. Until now, the unlimited plan was only available for subscribers to its TV service. With the plan, customers can get unlimited talk, text and data on four lines for $180 a month. There’s also an optional Stream Saver feature that lowers the video quality to a data-saving 480p resolution. AT&T said it could slow down the speeds if the customers goes over 22GB of data per month. AT&T’s plan doesn’t come with a hotspot like those offered by Verizon and T-Mobile.

Return to Unlimited

The move on the part of AT&T comes at a time when the wireless carriers are getting back in the unlimited game after shying away for years. That all changed when T-Mobile launched its unlimited plans and Sprint quickly followed suit. That has enabled the third- and fourth-place carriers to steal market share from AT&T and Verizon.

Earlier this week, Verizon shocked Wall Street when it announced it was launching an unlimited plan, which many saw as caving to pressure from T-Mobile and, to a lesser extent, Sprint. For $80 a month, Verizon wireless customers get unlimited data, talk and text on their device as long as they sign up for paper-free billing and AutoPay. Verizon is also charging $45 per line for four lines with unlimited data, talk and text with the same billing requirements. (See also: Verizon Launches Unlimited Data Plan.)

That announcement prompted T-Mobile to improve upon its unlimited data plan, and on Thursday, Sprint got in on the unlimited wars announcing it is adding high-definition video streaming and a mobile hotspot to its unlimited data plan. While AT&T and Verizon have been holdouts when it comes to offering unlimited data plans, it has been helping the likes of T-Mobile and Sprint when it comes to gaining market share. After all, consumers are watching much more content on mobile devices and don’t want to overpay for wireless data. Both T-Mobile and Sprint were able to increase their subscribers in the fourth quarter thanks in part to their unlimited plans and other aggressive promotions. Analysts expect T-Mobile and Sprint to continue to steal market share in 2017.

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