AMTM vs LDOS: How Amentum Holdings and Leidos Holdings Compare (2026)
Last updated August 2026
Short answer
LDOS is the larger of the two ($14.54B market cap): the incumbent the market prices for continued execution (8.82x forward earnings, beta 0.55). AMTM is the smaller challenger ($6.05B), priced similarly on forward earnings (8.92x): more room to run, but more to prove. The real question is which set of drivers you believe, and whether owning one (or both) leaves you over-concentrated.
AMTM vs LDOS: the tie-breaker metrics
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.
| Metric | AMTM | LDOS | What it tells you |
|---|---|---|---|
| Market cap | $6.05B | $14.54B | Size. The larger name is the incumbent; the smaller has more room to grow and more to prove. |
| Forward P/E | 8.92 | 8.82 | Valuation on next year's expected earnings, the same yardstick for both. Lower is cheaper for that growth; higher means the market is paying up. |
| Trailing P/E | 41.28 | 10.57 | Valuation on the last 12 months. A big drop from trailing to forward means the market expects earnings to jump, so more growth is already in the price. |
| Price vs 52-week range | 27% of range | 16% of range | Where today's price sits between the 52-week low and high. Near the high is momentum with less margin of safety; near the low is out of favor or a discount, depending on why. |
| Price / book | 1.31 | 2.90 | How much you pay over book value. Very high can signal an asset-light, high-return business or a rich price. |
Before you buy: how AMTM and LDOS affect your concentration
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. AMTM and LDOS 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 AMTM and LDOS 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.
What does Amentum Holdings (AMTM) do?
Amentum Holdings provides engineering, technology and mission support services to government customers, mostly in the United States. Its work spans nuclear operations and environmental remediation for the Department of Energy, space and science support for NASA, logistics, base operations and aviation sustainment for the Department of Defense, plus cyber, intelligence and critical digital infrastructure programs. The company reports in two segments, Digital Solutions and Global Engineering Solutions, and its revenue is overwhelmingly services and labor rather than manufactured hardware, which is a very different economic model from a traditional defense prime.
What does Leidos Holdings (LDOS) do?
Leidos Holdings is a large government services and technology contractor that builds and runs mission systems for U.S. federal agencies and allied governments. Its work spans intelligence and digital modernization, cybersecurity, defense systems, homeland security (including airport and border screening technology), and health services such as medical exams and health IT. Roughly the bulk of its revenue comes from the U.S. government, making it a prime contractor on long-duration programs rather than a commercial-product company.
AMTM vs LDOS: how do they differ?
Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.
- AMTM drivers: A record backlog that front loads visibility; Deleveraging as the main value lever.
- LDOS drivers: Large backlog and revenue visibility; Margin expansion and cash generation.
Which fits which kind of investor
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: Amentum is a government services contractor, so budget outcomes, continuing resolutions, shutdowns and shifting agency priorities flow almost directly into revenue. For LDOS, the overwhelming majority of Leidos revenue comes from the U.S.
AMTM or LDOS: which should you pick?
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 AMTM if you believe its drivers more; LDOS 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 AMTM and LDOS guides.
AMTM vs LDOS: the full fundamentals
AMTM. Amentum trades at a low single digit multiple of revenue that is typical for labor based federal services rather than the richer multiples defense hardware primes command, because margins are structurally thin. The gap between the ~$8.9 billion enterprise value and the ~$5.4 billion market cap is the leverage story in one number. The company pays no dividend, and fiscal third quarter results covering the period ended July 3, 2026 were scheduled for August 11, 2026, with consensus near $0.61 adjusted EPS on about $3.57 billion of revenue.
LDOS. In its most recent quarter (fiscal Q1 2026, ended early April 2026), Leidos posted about $4.4 billion in revenue, non-GAAP EPS of roughly $3.13, and adjusted EBITDA margin near 14%, and it raised full-year guidance. The stock trades at a low double-digit trailing P/E, a discount to the broader market that reflects its slow-growth, government-dependent profile. Figures are approximate and change with new filings and price moves.
Headline figures (approximate, August 2026): AMTM shows revenue (fy2026 guidance) ~$13.95B to ~$14.3B, backlog (fiscal q2 2026) ~$47.8B, book to bill ~1.2x, adjusted ebitda (trailing twelve months) ~$1.11B, market capitalization ~$5.4B to ~$5.8B (shares ~$23); LDOS shows revenue (ttm) ~$17.5B, fy2026 revenue guidance ~$18.0B to $18.4B, latest quarter revenue ~$4.4B (up ~4% YoY), total backlog ~$48B.
The bottom line: AMTM vs LDOS
AMTM and LDOS 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 AMTM and LDOS exposure against your real portfolio. It is not an investment adviser.
Wondering how AMTM or LDOS fits the portfolio you already own? Walnut is an AI investing app that connects your brokerage read-only and answers questions like that about your actual holdings: overlap, concentration, and how each position tracks the S&P 500. Compare the best AI portfolio analyzers or see the best AI investing apps in 2026.
Investing in Amentum Holdings with AI
Connect the broker you already use and ask Walnut's AI how AMTM fits what you actually hold: whether you own it already through a fund, what it would do to your concentration, and how it has tracked the S&P 500. Read-only by default, and you approve anything before it reaches your broker.
FAQ
What is the difference between AMTM and LDOS?
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Amentum Holdings provides engineering, technology and mission support services to government customers, mostly in the United States. Leidos Holdings is a large government services and technology contractor that builds and runs mission systems for U.S. They show up together because they share investment themes, but they are different businesses, so the better fit depends on which thesis you are expressing.
Is AMTM or LDOS the better stock?
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Neither is universally better. LDOS is the larger incumbent; AMTM is the smaller challenger and looks pricier on forward earnings. Walnut is informational, not investment advice. Compare what each does, the tie-breaker metrics above, and the risks, then decide which fits your thesis and what you already own.
Which is cheaper, AMTM or LDOS?
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On forward P/E (as of August 2026), AMTM trades at 8.92x and LDOS at 8.82x, so LDOS is the cheaper of the two on next year's expected earnings. A lower multiple is not automatically the better buy: a richer valuation can be justified by faster growth, and a lower one can reflect real risk. Weigh the multiple against how fast each business is compounding.
Should you own both AMTM and LDOS?
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Because they share themes, owning both concentrates you in that theme. That can be intentional (a focused bet) or accidental (less diversification than it looks). Walnut can show your combined exposure across both, and whether adding either over-concentrates you, before you buy.
What are the risks of AMTM vs LDOS?
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AMTM: Amentum is a government services contractor, so budget outcomes, continuing resolutions, shutdowns and shifting agency priorities flow almost directly into revenue. Contract concentration matters as well: a single large recompete lost at re bid can remove billions from backlog, and protests can delay awards already booked. Leverage near 3.2x leaves less room for error than a cash rich balance sheet would, and the company pays no dividend, so the equity return case depends on debt paydown and margin execution rather than income. The business also carries the usual government contracting exposures, including audits, False Claims Act and qui tam litigation, and cost disallowances, and Amentum has faced legacy suits inherited from acquired entities. Finally, it is a young public company assembled from two organizations, so integration slippage or a guidance reset would land on a share base with a short trading history to anchor expectations. LDOS: The overwhelming majority of Leidos revenue comes from the U.S. government, so budget delays, continuing resolutions, sequestration scenarios, and shifting administration priorities can directly pressure results. Contracts are frequently recompeted, and losing a large program or seeing an award protested can create lumpy revenue swings. Margins can be squeezed on fixed-price and cost-reimbursable work if execution slips or labor costs rise. The company also faces growing competition from both traditional peers and large commercial cloud and AI firms moving into federal work. Finally, its modest valuation reflects limited growth, so multiple expansion is not guaranteed even if execution stays solid.
Walnut is informational, not investment advice. This page is descriptive and not a recommendation to buy or sell AMTM or LDOS; figures are approximate and dated (as of August 2026). Verify current data before investing.