AT&T Stock’s Best Lever Is The Copper Network It Is Turning Off

AT&T stock’s strongest upside lever is not the customers it keeps adding, but the cost of the copper network it is finally switching off.

AT&T (T) stock has gone backwards while the business underneath it sped up, down about 10% over the trailing twelve months and roughly 14% below its 52-week high. The strongest upside case is not the fiber and phone accounts the company keeps winning, but the cost structure still attached to the copper network its customers are leaving.

The Copper Bill Is Falling Slower Than The Copper Revenue

Start with the segment AT&T is winding down, the small end of the business: Advanced Connectivity carries over 90% of service revenue and nearly all of adjusted EBITDA. In the second quarter of 2026, legacy service revenue declined 26% year over year, and legacy segment EBITDA declined about 46%. Profit falls faster than revenue there because copper stays powered until the last customer is off it, and those customers are only now clearing out: the company expects a couple hundred wire centers to have zero customers by the end of 2026, regulators have cleared it to discontinue legacy copper voice service at about 60% of its wire centers in California, and it has approval to discontinue legacy services at more than 30% of its wire centers nationwide by late 2026. Those lines move to AT&T Phone Advanced, fiber and wireless, and the cost of the wire center behind them can finally come out.

Margin Is Already Moving Before The Copper Is Gone

Management’s read is that the turndown has reached its tipping point. Consolidated adjusted EBITDA margin hit 39.1% in the second quarter of 2026, up 110 basis points year over year and the highest since the company refocused on Advanced Connectivity at the start of the decade. The company puts the margin gain down to scale in 5G and fiber, to its cost transformation work, and to lower legacy costs as the footprint shrinks. Strong margins of that kind are among the traits the Trefis High Quality Portfolio‘s holdings share. None of it re-rates a company this size overnight, though: the target is $4 billion in consolidated annual cost savings by the end of 2028, against about $127 billion of trailing-twelve-month revenue.

The Gap That Decides Whether The Cost Really Comes Out

The doubt worth taking seriously is that AT&T is buying its subscriber growth with price. Fiber ARPU declined 1.3% year over year in the second quarter of 2026. Excluding the lower-ARPU customers acquired from Lumen it was approximately flat year over year, and management expects some further pressure in the near term. But the number this case turns on sits in the legacy segment: the distance between its 26% revenue decline and its 46% profit decline. That gap widened from the first quarter of 2026, when legacy service revenue fell about 25% and legacy EBITDA about 40%, so convergence has to come from the profit decline easing, not from revenue falling faster.

This is not a stock that lurches: it has gained more than 30% in under two months just once since 2023, and that rally came in 2023 itself. The realistic upside is compounding rather than a spike, and the fair place to test that claim is alongside the market’s capital compounders.

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