Defence and Aerospace on Both Sides of the Atlantic
When Iran and the United States exchanged large‑scale strikes in early March, defence stocks briefly looked like the only corner of the market that knew which way was up. Within weeks, the easy “buy on conflict” trade had faded, leaving investors to distinguish between short-term war premiums and longer-term budget trends.
On the first Monday after the escalation, CNBC reported that global defence shares were “one of the few areas of strength amid a wider market downturn". In Europe, Germany’s Hensoldt and the UK’s BAE Systems both gained around 5% intraday, while Renk and Italy’s Leonardo rose more than 3% and 2%, respectively, even as the Stoxx 600 fell over 1% to a two‑week low. In the US, Lockheed Martin and Northrop Grumman advanced more than 3% and 6%, powered by expectations of higher demand for missile‑defence systems and long‑range strike capabilities. A separate Euronews piece on “market winners” from the Iran war notes that Lockheed hit a new all-time high at $676.70, with Northrop up 6% and RTX near 5% on the day, while European names such as Renk and Leonardo also rallied on hopes of larger NATO procurement and export orders.
However, that pop has not translated into a straight‑line rally. Military Times reports that the NYSE Arca Defence index fell nearly 8% in March, underperforming the broader S&P 500’s 5% drop, as investors took profits after a strong run into the conflict. The same article highlights that expectations for 2026 earnings growth at major US contractors such as General Dynamics had already been marked down from about 15% at the start of the year to around 12% by the end of March, reflecting concerns about production bottlenecks, supply chains and the timing of contract awards. A Financial Times analysis echoes this, noting that defence stocks dropped despite the war as markets weighed potential manufacturing constraints and uncertainty around US defence-spending negotiations.
UK names have largely tracked the European pattern. BAE Systems, Rolls‑Royce’s defence businesses and smaller contractors rallied sharply on the initial headlines, then gave back some gains as broader European equities sold off and investors refocused on valuation, execution risk and budget timelines rather than pure conflict headlines. Analysts quoted by Euronews emphasise that European defence budgets were already earmarked for growth in 2026 due to the Ukraine war; the Iran conflict mainly reduces political resistance to that spending rather than creating entirely new demand.
On both sides of the Atlantic, the net result is a sector that has outperformed over the past several years but where the 2026 war has produced only a transient additional boost. Future returns will depend less on headlines and more on how quickly governments convert announced rearmament plans into funded, multi-year procurement programmes and on whether contractors can expand capacity without sacrificing margins. For UK and US defence stocks alike, the market is signalling that the days of simply buying every conflict spike are over; from here, investors are demanding clearer visibility on sustainable earnings growth, capital discipline and the real scale of the post‑Ukraine, post‑Iran defence upcycle.