Defense Stocks: What Is Inside the Defense Modernization Theme

The theme applies one test: does material revenue come from defense and intelligence customers, meaning the US Department of Defense, the intelligence community, and allied governments, or from defense-adjacent specialty materials and communications used in defense electronics? That second clause is doing real work, because it is what admits the upstream suppliers whose products end up inside systems built by somebody else.

Two words carry the weight. The first is material. Plenty of companies hold a government contract somewhere. If a firm would look essentially the same with or without it, it is not a defense stock, and dropping that requirement turns the theme into a list of large technology and industrial companies with a Pentagon anecdote attached. The second is modernization. That word is why the theme is not simply the aerospace-and-defense sector in miniature: it points at the part of the budget that upgrades what is already fielded, rather than the part that builds more of it.

The consequence is a roster that looks wrong at first glance. The largest, most profitable, most obviously qualified defense companies in the world are not in it. That is not an oversight, and the section on exclusions below explains it in full. The theme spans layers instead: the software that ties systems together, the public-safety agencies running the same upgrade cycle on domestic budgets, and the materials and standards sitting underneath both. Those three do not depend on the same appropriation, which is the point of holding them together. For the general idea, see thematic investing.

Modernization spending is increasingly about what runs on the hardware rather than the hardware itself. This layer covers the software that fuses sensor feeds, intelligence reporting, and logistics data into something a commander or an analyst can act on, sold under long government programs to defense and intelligence customers. It sits first in the theme because it is the clearest expression of the idea the theme is built around: budgets are shifting from buying more platforms toward making existing platforms work together.

How this layer relates to the rest. This layer is the reason the theme exists in its current shape. Software is where new appropriations are being directed fastest, and it is the part of defense spending that the platform-heavy funds capture least well, so a modernization theme without it would simply be a slower version of an aerospace-and-defense index.

Modernization is not only a military program. Police, fire, and emergency services run the same upgrade cycle on a different budget line: replacing analog radio with mission-critical networks, adding body-worn video, and moving evidence and dispatch into software. The customers are federal, state, and local agencies rather than the Pentagon alone, and the money is appropriated rather than discretionary, which is what makes this layer belong alongside the defense names instead of in a generic technology theme.

How this layer relates to the rest. This layer is the theme's steadier middle. Its revenue is tied to public-safety and agency budgets that move on a different schedule from Pentagon procurement, and both names have converted hardware sales into recurring software and services, so the layer tends to be less sensitive to any single defense program than the rest of the roster.

Every system in the layers above is built out of physical parts and standardized radio protocols, and a small number of suppliers sit at chokepoints in both. This layer covers the qualified specialty materials that go into defense electronics and aerospace hardware, and the licensed wireless and video technology that communications standards are built on. It is the least visible part of the theme and the part with the longest substitution timelines, because qualifying a new material supplier or designing around a standard takes years rather than quarters.

How this layer relates to the rest. This layer is upstream of everything else. It does not depend on any single program being funded, because the materials and the standards feed a wide set of programs at once, which is why it behaves differently from the software and public-safety names when one specific budget line moves.

Read together, the theme is one idea expressed three ways. Modernization means upgrading a fielded capability rather than buying another copy of it, and each layer is a different point where that upgrade gets paid for. Palantir sells the software that makes existing sensors and systems useful together. Axon and Motorola Solutions sell the same upgrade to police, fire, and emergency services, where the budget comes from agencies rather than the Pentagon. Materion and InterDigital supply the qualified materials and the licensed standards that both of those depend on without either of them naming it as a line item.

The dependency runs upward. Standards and materials feed the devices and the systems, the systems generate the data, and the software layer is what turns that data into something a decision-maker uses. That is also the order in which substitution gets easier: a software vendor can in principle be replaced faster than a qualified alloy supplier can, even though the software name is the one with the durable-sounding government contracts.

The practical consequence is that the five names do not move for one reason. A defense budget reset would hit the perception of all of them and the revenue of very few of them quickly, because Materion and InterDigital earn plenty outside defense and public-safety budgets are appropriated separately. A general growth-stock derating would hurt Palantir and Axon while leaving Motorola Solutions comparatively untouched. Holding the layers together is what makes the theme behave differently from a single bet on Pentagon procurement, and understanding that is more useful than any ranking of the five.

A membership test is only credible if it excludes things, and this theme excludes the most obvious names in the sector. These are the companies people most often expect to find here, and the specific reason each one does not qualify.

• The defense primes (LMT, RTX, NOC, GD, BA). They pass the revenue test more comfortably than anything actually in the theme, and they are still left out. The reason is that the theme is about where new modernization spend is going, and the primes are the platform builders that the standard aerospace-and-defense fund already holds as its largest positions. Buying them individually alongside that fund would concentrate the same exposure twice. The theme covers them through the ITA ETF instead, and they are described one by one in the companion roundup.
• L3Harris (LHX) and Huntington Ingalls (HII). Both do real modernization work, in mission systems and electronic warfare for one and in unmanned naval systems for the other, but both are platform and systems integrators funded on the same appropriated program lines as the larger primes. They fail the same test for the same reason, and the same ETF holds them.
• Federal services contractors (LDOS, BAH). Government IT and consulting firms earn a large share of revenue from defense and intelligence customers, so the revenue test alone would admit them. What the theme is looking for is a product with a switching cost attached: software, an installed base, a qualified material, a licensed standard. Contracted services are recompeted, which is a different business shape, so they sit in the roundup rather than the theme.
• Launch and space names. National-security space is a genuine part of modernization, but launch providers, satellite operators, and lunar services have their own funding logic and their own failure modes. They belong to the space economy theme, where that structure is the thesis rather than a footnote to a defense roster.
• Cybersecurity platforms. Cyber is named in almost every modernization document, yet the large listed security vendors earn most of their revenue from commercial enterprises. Government is a customer segment, not the business, so they fail the materiality half of the test and are covered by the cybersecurity theme instead.

The primes deserve the plainest possible statement, because leaving them out looks like a mistake until you see the mechanism. Lockheed Martin, RTX, Northrop Grumman, General Dynamics, and Boeing are the biggest holdings of the aerospace-and-defense fund the theme names as its proxy. A theme that also held them individually would be paying for the same exposure twice and calling the second copy a thesis. So the theme spends its stock positions on what the fund underweights, and points at the fund for the rest. Those companies are covered name by name in the companion roundup, best defense stocks, which is the right page to read if the primes are what you came for.

The space exclusion points somewhere specific too. National-security space is real modernization spending, but launch and satellite businesses have their own funding logic, so they sit in the space economy theme where that structure is the thesis. A company can be a good business and still be the wrong expression of a given theme.

The same five names, grouped by the layer they occupy rather than ranked, so the shape of the theme is visible at a glance.

Not one of the 5 is a platform builder, and that absence is the theme's central design decision rather than an accident of what happened to be listed.

The passive route is an aerospace-and-defense fund, and here the relationship is unusually direct because the theme is defined partly against it. ITA, the iShares US Aerospace & Defense fund the theme names as its proxy, is anchored by the prime contractors, with the rest of the aerospace-and-defense universe spread behind them. It captures platform building thoroughly and the software, public-safety, and specialty layer only lightly. Axon is one of the few names that appears in both, which is a reminder that the two rosters overlap at the edges rather than being opposites.

A theme inverts the trade. You know exactly which five names you own, which layer each one represents, and what weight each carries, and you accept that five names is a narrower roster than a fund holds and a more concentrated one. Neither is automatically better, and in this case they are closer to complements than alternatives: the fund holds what the theme deliberately skips, and the theme holds what the fund underweights. Plenty of people run a broad fund as a core with a small thematic tilt beside it. For the fund route in full, see best defense ETFs.

A list of five names is an input, not a portfolio. What turns one into the other is structure: which layers you want exposure to, what weight each name carries, and whether the concentration you end up with was chosen or inherited.

• Decide the prime question first. Whether you hold the platform builders at all, and whether you hold them through a fund or directly, changes the character of the position far more than swapping one software name for another.
• Set target weights that sum to 100. Equal weighting across five names is a choice, and so is tilting toward the steadier public-safety layer. Both are defensible. Not deciding is what leaves you concentrated by accident after one name runs.
• Know how much of the roster is actually defense. Two of the five earn most of their revenue elsewhere. That dilution is deliberate, and it is also the thing most likely to surprise someone who bought the theme for pure defense exposure.
• Frame it against the S&P 500. A narrow thematic position should be judged against a broad benchmark, because the extra concentration has to be buying you something.
• Revisit as budgets and weights move. Policy-driven positions can look stable for years and then reprice quickly on a budget cycle, and thematic weights drift fast when the constituents have this much dispersion between them.

This is what Walnut is built for. You describe the thesis, the AI assistant proposes constituents and weights you can edit, the portfolio tracks as one performance line against the S&P 500, and you place trades you approve yourself at your own broker. Walnut is informational and does not tell you which stocks to buy.

For the companion view of which defense names are most widely held and discussed, including every prime this theme leaves out, see best defense stocks. For the adjacent theme that Materion also sits in, see critical materials.

The defense modernization theme is five companies across three layers, and the layering is the whole idea. Palantir represents the mission-software layer where new modernization budget is moving fastest. Axon and Motorola Solutions carry the same upgrade cycle into public safety, funded by agency budgets that move on their own schedule. Materion and InterDigital sit upstream in qualified materials and licensed standards, feeding many programs at once instead of depending on any one.

What defines the theme, though, is the absence. Lockheed Martin, RTX, Northrop Grumman, General Dynamics, and Boeing are the sector, and the theme holds none of them directly, because a fund already does that job and doing it twice is not a thesis. Understood as a flat list of five defense stocks, the roster looks idiosyncratic. Understood as the upgrade layer sitting deliberately beside a prime-heavy fund, it is a structure, and the structure is what you are deciding whether to own. Nothing here is a recommendation, and Walnut is not an investment adviser.