On February 2, 2026, AT&T closed its $5.75 billion purchase of Lumen's mass-market fiber business. The deal moved about 1 million residential and small business fiber customers to AT&T. It also moved roughly 4 million passings across 11 states.
Lumen kept the enterprise side. That means most of the accounts SpendAdvisor works on stayed put. But not all of them. Some small business fiber accounts got swept into the AT&T bucket. And the letters carriers sent about the change were, in a word, confusing.
Here is what actually happened, and how to figure out where your account landed.
What moved and what stayed
AT&T got the residential and small business fiber assets in cities like Denver, Seattle, Portland, Las Vegas, Phoenix, and Minneapolis. If you had a Quantum Fiber account under 1 Gbps at a single storefront, you probably got a letter in March or April telling you AT&T now owns the line.
Lumen kept everything on the enterprise side. Dedicated internet access. MPLS. SD-WAN. Wavelengths. Ethernet. Anything sold under the Lumen or CenturyLink Business brand with a term contract longer than one year, or with an SLA attached, stayed with Lumen.
The messy middle is small business fiber sold through the Quantum Fiber portal. Some of those accounts moved. Some did not. It depended on the address, the plan tier, and whether the account had a business tax ID on file.
How to tell which company holds your account today
Pull your most recent bill. Look at three things.
The remit-to address on the payment stub. If it now says AT&T in Dallas, the account moved. If it still says Lumen or CenturyLink in Louisiana, it stayed.
The account number format. AT&T account numbers are 12 digits. Lumen kept its older format with a mix of letters and numbers.
The support phone number. AT&T Business support routes through 800-321-2000. Lumen Business is still 877-453-8353. If you call the old Lumen number and get transferred, that is your answer.
Why this matters for your bill
If your account moved to AT&T, three things change.
Your contract terms carried over, but the renewal path did not. AT&T has different pricing tiers and different promo windows. The rate you signed at with Lumen is locked until your end date, and then you renegotiate with AT&T.
The fees on the bill got renamed. Lumen's Internet Cost Recovery Fee became AT&T's Cost Assessment Charge. Same fee, new label, roughly $3.99 a line. Not a tax. Straight carrier revenue.
Support tickets now go through the AT&T Business portal. The old Lumen Control Center still works for enterprise accounts, but the moved fiber accounts are locked out.
What to do in the next 90 days
Check your renewal date. Put it in your calendar. If you are inside the 90-day window, start the renegotiation now. AT&T is aggressive on new-customer promos in the acquired markets because they want to hit retention targets. That gives you room.
If you have offices in more than one city, check each address separately. We have seen accounts where the Denver location moved to AT&T and the Phoenix location stayed with Lumen. Same company, same billing contact, two different carriers.
And if you get a letter saying your service is being "upgraded" as part of the transition, read it twice. In several cases the upgrade came with a new 36-month term. That resets your renewal clock and locks you in at the current rate.
The short version
Enterprise stayed with Lumen. Consumer and most small business fiber moved to AT&T. Your job is to find out which side of the line your account sits on before your contract auto-renews.
Upload your bill and we will tell you which carrier holds your account and what your fair market rate looks like in your city.
Related reading
→ AT&T Business fiber pricing and options → Lumen enterprise services overview → What a SpendAdvisor bill review looks like → Denver business internet market rates