AD vs AMT: How Array Digital Infrastructure, Inc. and American Tower Corporation Compare (2026)

Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

Reading it: AMT is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. AD and AMT share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined AD and AMT exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

Array Digital Infrastructure owns and leases about 4,400 cell towers across the United States. It used to be United States Cellular Corporation, a regional wireless carrier, until it sold its retail wireless operations to T-Mobile for roughly $4.3 billion (closed August 2025) and renamed itself Array that same month. What survived the sale is the real estate: the towers, the ground leases, and the residual spectrum. The company then sold 3.45 GHz and 700 MHz licenses to AT&T for ~$1.018 billion (closed January 2026, producing a ~$156.6 million book gain), and further licenses to Verizon for ~$1.0 billion and T-Mobile for ~$168 million (closed June 2026), while retaining its C-band holdings. Headcount is about 60 people. Telephone and Data Systems, the Carlson-family-controlled parent, holds roughly 81.9% of the economics and about 95.9% of the voting power.

Full AD guide

American Tower Corporation (NYSE: AMT), founded in 1995 and headquartered in Boston, is a real estate investment trust that owns, operates, and develops multitenant communications real estate. Its core business is leasing vertical space on wireless towers to mobile network operators, government agencies, and broadcasters under long-term contracts with annual escalators, generating 97% of 2025 revenue from property operations. Beyond towers, AMT owns CoreSite, a portfolio of 30 U.S. data centers offering colocation and interconnection services to enterprises, cloud providers, and network operators, which has become a fast-growing second revenue engine. The company manages nearly 150,000 communications sites across the Americas, Europe, Africa, and Asia-Pacific, providing global scale that smaller peers cannot easily replicate.

Full AMT guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• AD drivers: The T-Mobile master license agreement converts internal towers into rent; Remaining spectrum is an unmonetized asset sitting inside the enterprise value.
• AMT drivers: 5G Densification and Mid-Band Upgrades; CoreSite and AI-Driven Data Center Demand.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: The single largest risk is tenant concentration in the other direction: the T-Mobile MLA provides interim licenses of up to 30 months on the remaining ~1,800 towers not covered by the long-term commitment, so a large block of sites faces a potential decommissioning cliff once T-Mobile finishes its network integration. For AMT, the most immediate risk is customer concentration: in 2025, four carriers (T-Mobile at 18%, AT&T at 17%, Verizon at 14%, and Telefonica at 10%) collectively represented roughly 59% of total revenue, so any material lease dispute, consolidation event, or technology shift (such as carriers building private networks or relying on low-earth-orbit satellites) could disproportionately hurt results.

Growth-minded investors who believe the theme has years to run tend to accept the richer multiple for more upside; value-minded investors lean toward the cheaper forward earnings and steadier profile. Pick AD if you believe its drivers more; AMT if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the AD and AMT guides.

AD. Standard multiples do not describe this security well. The trailing P/E near the high single digits to mid teens (data providers disagree) is measuring one-time spectrum gains, not rent, and EV against guided adjusted OIBDA of ~$50 to $65 million screens far above where American Tower, Crown Castle and SBA Communications trade. Both distortions have the same cause: unmonetized C-band spectrum and cash sit inside the enterprise value while contributing no operating income, and legacy wind-down costs still sit inside the expense line. The 52-week range of ~$33.71 to ~$79.17 also overstates the damage, since roughly $44.25 of that decline was paid out as special dividends, leaving total return over the year approximately flat. Sell-side coverage is thin, with a consensus target near $46.34. Q2 2026 results were scheduled for August 7, 2026, the day after this snapshot.

AMT. AMT's trailing P/E of approximately 27x is well below its own 3-year average of roughly 45x and its 10-year average of roughly 56x, reflecting both earnings normalization after a period of large one-time items and a broader re-rating of rate-sensitive REITs in a higher-for-longer interest rate environment. For tower REITs, investors typically focus on AFFO per share rather than GAAP earnings, because the latter is heavily influenced by depreciation and one-time currency gains or losses. On that basis, FY 2025 delivered high-single-digit AFFO per share growth, and management's 2026 guidance projects continued quarterly revenue in the $2.67 billion to $2.77 billion range per quarter, suggesting mid-single-digit full-year growth if realized.

Headline figures (approximate, August 2026): AD shows revenue (ttm) ~$188 million, with full-year 2026 guided to ~$200-215 million, q1 2026 revenue ~$52 million total, site rental ~$51 million (up ~92% year over year), adjusted oibda guidance (2026) ~$50-65 million, on capex of ~$25-35 million, market cap / enterprise value ~$3.1 billion at ~$35.65 a share, EV ~$4.05 billion; AMT shows revenue (q1 2026) ~$2.74 billion, revenue (fy 2024, most recent full year) ~$10.13 billion, adjusted ebitda (q1 2026) ~$1.84 billion (margin ~67%), affo per share (q1 2026) ~$2.84 (up ~3.3% year-over-year).

AD and AMT are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined AD and AMT exposure against your real portfolio. It is not an investment adviser.