Shares of mobile phone service carriers fell in after-hours trading on Thursday after SpaceX (SPCX) announced it reached an agreement to acquire a nationwide low-band spectrum license portfolio.

Verizon (VZ) stock fell nearly 7%, AT&T (T) stock dropped by nearly 8%, and T-Mobile (TMUS) stock declined by 7% as the announcement stoked concerns that Starlink would disrupt the wireless telecom space.

SpaceX shares gained 3% in extended trading.

SpaceX purchased a spectrum portfolio of up to 14 megahertz of paired spectrum in the 800 MHz band from Grain Management LLC, an investment firm specializing in digital infrastructure. The companies did not disclose the amount of the transaction, which is subject to FCC approval.

SpaceX said in a statement that, once it receives FCC approval, it intends to connect its Starlink satellite-to-mobile constellation in space with an advanced terrestrial network. The company said this new low-band spectrum will enable the network to reach customers' devices through walls and buildings as it aims to create total coverage, even in dead zones.

"This is the last critical piece of the spectrum puzzle needed for SpaceX to provide complete phone coverage in America," SpaceX CEO Elon Musk posted on X.

The move marked an escalation in the company's consumer telecom ambitions — something it hasn't exactly kept a secret.

During the company's earnings call in August, SpaceX COO Gwynne Shotwell said Starlink planned to build a terrestrial wireless network and go after Verizon, AT&T, and T-Mobile's customers. She said SpaceX also plans to launch its second generation of Starlink Mobile satellites in 2027.

"I anticipate us to be able to acquire quite a few of their [AT&T, Verizon, and T-Mobile's] customers because I think our service will be better," Shotwell said on the earnings call.

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