Unlimited data is no more at AT&T.

In a press release, AT&T gently eased into the termination. It began with the looming U.S. “wireless spectrum crunch.” It then shared about its effort to invest “billions” to expand its network capacity.

However, AT&T said it needs “immediate measures to help address network congestion.”

Therefore, starting Oct. 1, it will start reducing speed for the top five percent of its heaviest data users. The speed reduction effectively serves as a data cap by discouraging usage and slowing the rate of data flow.

It’s unclear how AT&T will implement its five percent rule.

“The amount of data usage of our top five percent of heaviest users varies from month to month, based on the usage of others and the ever-increasing demand for mobile broadband services. To rank among the top five percent, you have to use an extraordinary amount of data in a single billing period,” stated AT&T.

The company emphasized that the move will not affect the majority of AT&T customers. Instead, it’s targeted towards a minority of users who are responsible for a disproportionately large portion of data usage.

These users typically stream large amounts of video and music over the wireless network (as opposed to Wi-Fi network). They use 12 times more data than the average user of all other data plans, stated AT&T.

If these users want unfettered access going forward, they need to switch to a tiered usage plan and pay for their high data usage, stated AT&T.  Otherwise, they will see slower data once they hit their limit. 

At the end of its press release, AT&T took the opportunity to make a plug for its proposed acquisition of T-Mobile.

It stated:

“But even as we pursue this additional measure, it will not solve our spectrum shortage and network capacity issues. Nothing short of completing the T-Mobile merger will provide additional spectrum capacity to address these near term challenges.”