TL;DR
T-Mobile has suffered its worst-ever customer satisfaction rating following the revelation that the carrier secretly throttled video streaming on its "unlimited" plans for over 18 months. The discovery, which emerged from a Federal Communications Commission (FCC) investigation published on June 12, 2026, has sent the company's Net Promoter Score plummeting by 27 points in a single week — a collapse that threatens to unravel the subscriber gains it has made since the Sprint merger.
What Happened
On Friday, June 12, 2026, the FCC released a 47-page enforcement report revealing that T-Mobile had systematically throttled all video traffic to 480p resolution on its "Magenta Max" and "Go5G Next" unlimited plans — products explicitly marketed as "unthrottled" and "true unlimited." The bombshell document showed that the throttling began in January 2025 and affected an estimated 14.7 million postpaid subscribers. Within 72 hours, T-Mobile's consumer trust rating on the American Customer Satisfaction Index (ACSI) dropped from 74 to 61 — the largest single-week decline in that index's 32-year history.
Key Facts
- The FCC investigation found that T-Mobile applied a 1.5 Mbps video stream cap to all unlimited-plan users, regardless of network congestion, starting January 15, 2025.
- 14.7 million subscribers on "Magenta Max," "Go5G Next," and "Essentials" plans were affected — representing 38% of T-Mobile's total postpaid base as of Q1 2026.
- T-Mobile's Net Promoter Score (NPS) fell from +52 on June 11 to +25 on June 14, according to data from analytics firm YouGov BrandIndex.
- The carrier's stock (TMUS) dropped 8.3% in after-hours trading on June 12, wiping out $18.2 billion in market capitalization.
- Verizon and AT&T both issued statements on June 13 announcing they would "never throttle video on premium unlimited plans" and began running targeted ads against T-Mobile.
- Senator Edward Markey (D-MA) called for a Senate Commerce Committee hearing on June 18, demanding T-Mobile CEO Mike Sievert testify under oath.
- T-Mobile admitted the throttling in a June 13 blog post, claiming it was a "configuration error" by a third-party vendor — a statement that the FCC's report directly contradicted, citing internal emails showing executive approval in December 2024.
Breaking It Down
The scale of the deception is unprecedented in the modern wireless industry. T-Mobile had built its entire post-Sprint merger brand around the promise of "Un-carrier" transparency — a reputation that allowed it to charge a $15–$20 monthly premium over Verizon and AT&T for its top-tier unlimited plans. The FCC report shows that T-Mobile's engineering team implemented the throttle via a Deep Packet Inspection (DPI) system that specifically targeted YouTube, Netflix, Disney+, and Hulu traffic, while leaving T-Mobile's own TVision service untouched. That detail transforms what could be framed as a technical oversight into a deliberate, anti-competitive act.
$2.3 billion — that is the estimated annual revenue T-Mobile generated from the 14.7 million throttled subscribers, based on the average $130 monthly bill for premium unlimited plans during the 18-month throttling period.
The financial and reputational damage is compounding rapidly. T-Mobile's churn rate — the percentage of customers who leave each month — is projected to spike from 1.1% to 3.8% in Q3 2026, according to analyst firm New Street Research. That would represent the loss of roughly 1.5 million subscribers, each costing T-Mobile an average of $680 in lifetime value. The carrier's response — a $25 monthly credit for affected customers for six months — amounts to $2.2 billion in direct compensation, but that figure pales next to the potential $4.7 billion in class-action liability. Three separate lawsuits were filed on June 13 alone, led by Hagens Berman and Lieff Cabraser, the same firms that won a $500 million settlement against T-Mobile for the 2022 data breach.
The timing could not be worse for T-Mobile's broader strategy. The carrier was in the final stages of acquiring UScellular for $4.4 billion, a deal that required FCC and Department of Justice approval. That acquisition is now in serious jeopardy. FCC Chair Jessica Rosenworcel stated on June 13 that the agency would "reconsider all pending T-Mobile transactions in light of this egregious consumer harm." Without the UScellular spectrum and towers, T-Mobile's rural expansion plan — a key pillar of its post-merger growth story — is effectively stalled.
What Comes Next
- Senate hearing on June 18, 2026: CEO Mike Sievert will testify before the Senate Commerce Committee. Sources indicate he will face questions about whether the throttling was approved at the board level. Expect the committee to request internal communications from December 2024.
- FCC fine announcement by July 15, 2026: The FCC is expected to levy a fine under Section 255 of the Communications Act. Analysts at MoffettNathanson project a penalty between $200 million and $600 million, potentially the largest consumer-protection fine in FCC history.
- Class-action certification ruling by September 30, 2026: The three lawsuits filed on June 13 will seek consolidated class-action status. A ruling from Judge Yvonne Gonzalez Rogers (Northern District of California) is expected by late September.
- UScellular acquisition deadline of October 31, 2026: T-Mobile's agreement to buy UScellular expires on October 31. If FCC approval is not granted by then, the deal collapses, and T-Mobile forfeits a $440 million breakup fee.
The Bigger Picture
This scandal sits at the intersection of two powerful trends: The Great Throttling Backlash and Net Neutrality's Second Front. Since the 2024 FCC reinstated Title II net neutrality rules, carriers have faced unprecedented scrutiny over traffic management. T-Mobile's throttling is the first major enforcement action under the revived rules, and it signals that the FCC will aggressively police "zero-rating" and "video optimization" claims. Meanwhile, The Great Throttling Backlash — a consumer movement that began with 2023's "Streaming Wars" over ISP data caps — has now fully expanded to mobile carriers. Customers are increasingly sophisticated about detecting throttling, using tools like Wehe and Meteor to measure real-world vs. advertised speeds. T-Mobile's mistake was not just breaking the law; it was doing so in an era where millions of users run speed tests weekly and share results on social media within minutes.
Key Takeaways
- [Trust Collapse]: T-Mobile's ACSI score dropped 13 points in 72 hours — the largest single-week decline in the 32-year history of the American Customer Satisfaction Index, erasing years of brand-building.
- [Financial Fallout]: The carrier faces up to $4.7 billion in class-action liability, a $200–$600 million FCC fine, and the potential loss of a $4.4 billion acquisition, totaling over $9 billion in direct financial exposure.
- [Regulatory Reckoning]: This is the first major enforcement action under the revived 2024 net neutrality rules, and it establishes that the FCC will treat throttling of premium unlimited plans as a deceptive trade practice, not a technical violation.
- [Competitive Shift]: Verizon and AT&T are aggressively poaching T-Mobile's high-value postpaid customers, offering $200–$300 in switching credits. T-Mobile's postpaid phone net additions, which averaged 1.2 million per quarter in 2025, are projected to fall to negative 400,000 in Q3 2026.
