This post has been updated with a comment from AT&T
The US Federal Communications Commission today announced it will fine AT&T $100 million for not adequately informing customers with “unlimited” data plans that it would drastically slow down their data speeds. It is the largest fine ever imposed by the agency.
AT&T hasn’t offered unlimited data plans since 2009, but millions of customers have had them grandfathered in. Ever since 2011, the wireless carrier has been throttling those subscribers’ download speeds when they crossed a certain threshold. And it throttled them by a lot—down to 512 Kbps compared to about 40 Mbps, or nearly 80 times slower.
The FCC is fining AT&T under the 2010 Open Internet Transparency Rule, which requires telecoms companies to provide “accurate information” about the broadband and mobile data speeds customers will receive. The FCC argues that if AT&T marketed its mobile plans as unlimited, and then effectively limited the amount of data its users could download at any given time, then it was misleading its customers.
ATT said it would “vigorously dispute” the fine and insisted that it had complied with the law. But its argument did not win over the FCC. ”Unlimited means unlimited,” said FCC Enforcement Bureau Chief Travis LeBlanc in a statement.
Update 4:13pm: AT&T legal counsel Michael Balmoris issued the following statement to Quartz via email:
This is a proposed fine. They are alleging violations, which we dispute. We have legal recourse.
Editor’s note: The photo on this post has been changed.