What Could Surprise Comcast Stock Investors On The Upside?

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Comcast (CMCSA) stock closed on October 23, 2026, 27.3% below its highest close of the past year. The company lost 144,000 broadband subscribers in its third quarter. Trading at 7.1 times earnings, compared with 22.9 for the S&P 500, the stock price appears to assume those losses go on. Yet one business inside Comcast’s home connectivity arm kept growing through that quarter. Which business is it, and how far has it come?

Comcast Keeps Adding Wireless Lines

That growing business is wireless phone service, which management says is built on Comcast’s existing broadband customer base. The company ended the third quarter of fiscal 2026 with 10.6 million wireless lines, up 18% from a year earlier. Wireless service revenue grew nearly 15% in the quarter, while convergence revenue, representing Comcast’s combined broadband and wireless revenue, fell 2%.

Customers are also choosing pricier plans. Premium unlimited plans made up about 40% of Comcast’s postpaid phone connects in the quarter, up from 30% the quarter before. On its October 22, 2026, call, management called mobile “a tremendous growth opportunity” and described it as a capital-light model.

How Big Could Comcast’s Wireless Business Get?

Management said wireless has reached nearly 18% penetration of Comcast’s residential broadband base. Those lines also make up only about 7% of the total wireless lines Comcast could address in the areas its network covers, a figure management described on the call as huge upside.

Wireless is not yet big enough to lift Comcast’s home business. It sits inside Residential Connectivity & Platforms, which brought in $70.7 billion in fiscal 2025, down 1.2% from a year earlier. Management said third-quarter wireless growth only partly offset continued pressure on broadband revenue.

So far, the stock has lagged the market. Comcast stock lost 13.4% over the year to October 23, 2026, including dividends, while the S&P 500 returned 15.1%.

What Must Go Right For Comcast In Wireless?

Comcast has to turn free lines into paying customers. About half of its residential postpaid phone connects in the third quarter came from customers taking a free line. Management said the company now converts 70% of those free lines into paying relationships.

The market is also crowded. On the October 22 call, management said that wireless remains competitive, and that customers switched providers a little less often in the quarter as new combined offers reached the market.

Comcast is expected to report its fourth quarter in January 2027. Net wireless lines added, which totaled 368,000 in the third quarter, is the number to watch in that report.

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