In December 2011, SpectrumCo, a JV between Comcast, Time Warner Cable, and Bright House Networks (the latter two are now part of Charter Communications) announced that it had reached an agreement to sell its 122 Advanced Wireless Services (AWS-1) spectrum to Verizon for $3.6 billion. The press release announcing the transaction included the following note:

“The companies also announced that they have entered into several agreements, providing for the sale of various products and services. Through these agreements, the cable companies, on the one hand, and Verizon Wireless, on the other, will become agents to sell one another's products and, over time, the cable companies will have the option of selling Verizon Wireless' service on a wholesale basis. Additionally, the cable companies and Verizon have formed an innovation technology JV for the development of technology to better integrate wireline and wireless products and services.”

For a few years, not much happened (May 2015: “We have the MVNO agreements with Sprint and Verizon, but we don't have anything to announce right now.”). But then, in 2017, Comcast launched Xfinity Mobile. A year later, Charter followed suit with Spectrum Mobile. The cable companies now had their own wireless offerings – with services supported by the mobile virtual network operator (MVNO) agreement announced with Verizon in 2011.

Fast forward to today and we can see that these efforts have started to bear fruit: as of Q3 FY21, Charter and Comcast had 3.2 million and 3.7 million wireless subscribers, respectively. Despite the fact that they only sell to customers within their cable geographies, its estimated that the cable companies have accounted for roughly 30% of wireless industry net adds over the past year. Based on recent trends, Comcast and Charter will each have more than five million wireless subscribers by the end of 2023. (Charter CFO Chris Winfrey: “I think our [wireless] penetration potential on our 30 million Internet customer relationships is very, very high.”)