SpaceX's agreement to buy Grain Management's 800 MHz spectrum has been read as the opening shot of a potential fourth US nationwide mobile carrier. That reading may only be half right.

At a minimum, SpaceX has bought an option, and with it increased negotiating leverage over the incumbents. What it has not bought is a fully operational nationwide mobile network.

On 8 October SpaceX nationwide 800 MHz portfolio: up to 14 MHz of paired low-band spectrum, for a reported c.$8bn and subject to Federal Communications Commission (FCC) approval. It is the third and most consequential step in what increasingly looks like a deliberate accumulation strategy.

It follows the c.$17bn deal for EchoStar's satellite spectrum and a $2.6bn purchase of EchoStar's ground-based cellular licences. SpaceX now holds a credible, multi-layer spectrum stack spanning satellite and terrestrial frequencies.

The direction of travel was set out at the June 2026 IPO. The ambition is to turn Starlink from a rural broadband provider into a global connectivity platform spanning broadband, mobile and hybrid satellite-terrestrial networks. This deal extends its direct-to-device (D2D) offer, where satellites connect straight to ordinary mobile handsets.

Spectrum is the range of radio frequencies that carry mobile signals. Think of it as invisible infrastructure: each band is a lane of airwaves, and governments license exclusive use of those lanes, in the US through the FCC, usually by auction. Without a licence, an operator cannot transmit. Frequencies are measured in hertz (MHz, GHz), and the amount an operator holds (14 MHz here) determines how much traffic it can carry, much as more lanes on a motorway carry more cars.

The frequency also matters, because it dictates how far a signal travels and how well it gets through walls.

Low-band spectrum, broadly frequencies below 1 GHz, carries over long distances and penetrates buildings far better than mid- or high-band. It is the foundation layer of every major US carrier's network, and the reason rural and in-building coverage works at all.

According to T-Mobile, more than 70% of mobile traffic takes place indoors: at home, in the office or in shops. This is where terrestrial networks have a fundamental advantage. Buildings and other obstacles make it difficult for signals travelling from space to reach customers reliably.

High-band is the opposite trade-off: enormous capacity in dense urban areas, but limited range and a need for dense infrastructure. By securing low-band, SpaceX addresses the fundamental weakness of satellite-to-phone connectivity: reliable indoor coverage.

A spectrum licence is the right to transmit. A carrier-grade mobile network is something else entirely: ubiquitous indoor coverage, high capacity, seamless mobility and 99.999% ("five nines") availability.

Building that nationally from scratch is likely to take at least five years and tens of billions of dollars to reach meaningful population coverage at the standard US consumers expect. SpaceX would need terrestrial sites, backhaul (the links connecting cell sites to the core network) and operational infrastructure. Its relatively narrow 14 MHz low-band holding also limits capacity in cities.

The gap between holding spectrum and running a carrier remains enormous.

Each spectrum purchase ratchets up pressure on the incumbent mobile network operators (MNOs). Investors clearly read it as a competitive threat: on 9 October AT&T fell 10.8%, T-Mobile 13.3% and Verizon 10.1%.

SpaceX now holds a credible threat of becoming a fourth national carrier. That gives it three options: build, partner, or negotiate wholesale access to an incumbent's terrestrial network.

One of the greatest opportunities is wholesale. Pressuring an incumbent into a favourable mobile virtual network operator (MVNO) agreement, where SpaceX rents capacity on someone else's network rather than owning one, may be the most capital-efficient outcome of all.

The market's other reaction was just as instructive. Tower stocks rose on the news: Crown Castle +15.6%, American Tower +9.3% and SBA Communications +7.3% on 9 October.

The logic is straightforward. If SpaceX builds terrestrially, it needs towers or small cells, and the tower companies are the landlords. Crown Castle derives 89% of its tower revenue from AT&T (27%), T-Mobile (40%) and Verizon (22%). A fourth national carrier would be an incremental tenant, not a replacement. Even a hybrid, partnership-led network needs terrestrial infrastructure.

While a wholesale deal could reduce demand for new sites, limiting the upside for tower companies, it would reinforce the strategic importance of existing terrestrial networks.

Communication towers have been described as “the best business ever”, and for good reason. A tower can be profitable with just one tenant, while each additional tenant generates incremental revenue at minimal additional cost. This practice, known as colocation, drives high incremental profit margins and, combined with low maintenance capex, has the potential to generate substantial free cash flow available for distribution to investors.

Whether the endgame is a wholesale agreement, a hybrid satellite-terrestrial joint venture or a genuine fourth carrier, SpaceX has strengthened its hand. The Grain deal may be as much about making the cost of not dealing with SpaceX prohibitively high for the incumbents as it is about building a network.

What has become clearer is that a fully functioning mobile network still requires terrestrial infrastructure investment. Satellites extend coverage; towers, backhaul and sites carry the load.

This article first appeared in Investment Week on 19 October 2026

Important Information

This article is issued by Gravis Advisory Limited (“GAL” or the “Firm”), which is authorised and regulated by the Financial Conduct Authority. GAL’s registered office address is 24 Savile Row, London, United Kingdom, W1S 2ES. The company is registered in England and Wales under registration number 09910124.

TM Gravis Digital Infrastructure Income Fund (the “Fund”) is a sub-fund of TM Gravis Funds ICVC, which is a UK UCITS scheme and an umbrella company for the purposes of the OEIC Regulations. The Authorise Fund Manager of TM Gravis Funds ICVC is Thesis Unit Trust Management Limited (TUTMAN), Exchange Building, St John’s Street, Chichester, West Sussex, PO19 1UP. TUTMAN is authorised and regulated by the Financial Conduct Authority. GAL is the investment manager of the Fund.

Any decision to invest in the Fund must be based solely on the information contained in the Prospectus, the latest Key Investor Information Document and the latest annual or interim report and financial statements. GAL does not offer investment advice and this article should not be considered a recommendation, invitation or inducement to invest in the Fund. Prospective investors are recommended to seek professional advice before making a decision to invest.

Your capital is at risk and you may not get back the full amount invested. Past performance is not a reliable indicator of future results. Prospective investors should consider the risks connected to an investment in the Fund, which include (but are not limited to) market risk, counterparty risk, inflation and interest rate risks and the risks of investing in real estate and related industries. Please see the Risk Factors section in the Prospectus for further information.

This article has been prepared by GAL using all reasonable skill, care and diligence. It contains information and analysis that is believed to be accurate at the time of publication but that is subject to change without notice. It is not intended for distribution to, or use by, any person or entity in any jurisdiction or country where such distribution or use would be contrary to local law or regulation. Any recipients outside the UK should inform themselves of and observe any applicable legal or regulatory requirements in their jurisdiction.