Verizon, AT&T and T-Mobile sell their SpaceX network plans in the United States

Telecommunications stocks sold off on Friday after that of Elon Musk EspaceX announced an agreement to purchase a nationwide spectrum portfolio, aimed at expanding its Starlink Internet to mobile service.

Verizon closed down 8.75% on the news, its worst day since July 2002. Shares of T-Mobile fell by 13.27% while AT&T fell 9.81%, each recording its worst days since 2013 and 2000, respectively.

SpaceX stock rose slightly, about 1% on the day.

The deal includes the acquisition of spectrum from Grain Management, which SpaceX described as a “licensing portfolio of up to 14 megahertz of paired spectrum in the 800 MHz band,” in a statement released Thursday.

FCC Chairman Brendan Carr, whose agency will oversee approval of the deal, said competition in the spectrum market was “very good news for American consumers” in an interview with CNBC.

“We’re probably going to introduce over $100 billion of spectrum into the market over the next couple of years, so we’re seeing a lot of competition,” Carr told CNBC’s “Squawk on the Street” on Friday.

“There are going to be movements in the market. People are going to try to be more competitive, more innovative, and I think that’s great. We’re going to see how that plays out. It’s not ultimately up to us to pick the winners and the losers,” he added.

Several SpaceX analysts welcomed the new spectrum deal, with Evercore ISI writing that the rocket maker “now has the outlines of a real network” alongside its existing satellite capabilities. JPMorgan wrote that the acquisition made Starlink Mobile’s long-term opportunity “more credible.”

“That said, we continue to see limited near-term risk for U.S. wireless incumbents given the time, infrastructure and capital required to build a competitive terrestrial network,” the analysts added in a note published Friday.