Defense budgets are surging globally. IMF data reveals fiscal risks, sovereign debt implications, and capital market opportunities for institutional investors.

Key Highlights

  • Global defense spending reached USD 2.63 trillion in 2025, up from USD 2.48 trillion in 2024, driven by Europe and the Middle East.
  • IMF research finds a typical defense spending boom raises military outlays by 2.7 percentage points of GDP, with two-thirds deficit-financed.
  • Public debt rises by roughly 7 percentage points within three years of a peacetime boom; wartime buildups push that figure closer to 14 percentage points.
  • All 32 NATO members met the 2% GDP defense target in 2025 for the first time, with a new 5% GDP commitment set for 2035.
  • Global public debt already stands at 93.9% of GDP and is projected to breach 100% by 2028 under current fiscal trajectories.

A Structural Shift, Not a Cyclical Spike

The world is rearming at a pace not seen since the Cold War. According to the International Institute for Strategic Studies, global defense spending reached USD 2.63 trillion in 2025, a rise of roughly 6% from the previous year in nominal terms and 2.5% in real terms. Europe and the Middle East were the primary drivers of that uplift.

The catalyst is not difficult to identify. Geopolitical fractures, from the Russia-Ukraine war to the ongoing US-Iran conflict that has disrupted Strait of Hormuz traffic and pushed oil above USD 100 per barrel, have forced governments to fundamentally reassess their security architectures. The rearmament underway is no longer a temporary allocation adjustment. It is a structural repositioning of public expenditure priorities.

The IMF's April 2026 World Economic Outlook, which devoted two analytical chapters to the macroeconomics of defense spending and conflict recovery, provides the most comprehensive institutional framework to date for evaluating what this repositioning means for growth, debt, and citizen welfare over the medium and long term.

The Short-Term Case: Defense as Demand Stimulus

Defense expenditure, when examined through a conventional macroeconomic lens, generates demand. It creates jobs in manufacturing, engineering, and logistics. It procures domestically produced goods in many cases. It stimulates adjacent industries in semiconductors, communications, and advanced materials. For economies with spare capacity, the short-term fiscal multiplier can be meaningful.

The IMF's research confirms this. Defense spending multipliers average close to 1, meaning each dollar of defense outlay generates roughly a dollar of economic output in the near term. European countries accelerating procurement are seeing industrial order books fill up, employment in defense manufacturing rise, and technology transfer into civilian sectors begin.

NATO data reinforces the scale of this stimulus. European allies and Canada increased defense spending by 20% in 2025 compared to 2024 in real terms, collectively investing more than USD 574 billion. For the first time in recorded NATO history, all 32 member states met the 2% of GDP defense threshold. Poland led at 4.48% of GDP.

For defense manufacturers and their supply chains, capital allocation toward the sector carries visible upside. Arms sales by the world's largest weapons producers have doubled in real terms over the past two decades, according to IMF data. Demand visibility is high, with NATO's Hague Summit in 2025 committing allies to a 5% of GDP spending target by 2035.

The Medium-Term Warning: Debt, Deficits, and Crowded Priorities

The IMF's analysis introduces significant caution around what follows the initial stimulus. The typical defense boom, lasting approximately two and a half years, leaves a fiscal footprint that extends far longer. Fiscal deficits worsen by roughly 2.6 percentage points of GDP. Public debt rises by about 7 percentage points within three years. External balances deteriorate. And when spending occurs during active conflict, the consequences are sharper: public debt rises by approximately 14 percentage points and social spending contracts.

These are not abstract projections. The fiscal environment into which this spending boom is arriving is already strained. The IMF's Fiscal Monitor notes that global public debt reached 93.9% of GDP in 2025 and is on course to breach 100% by 2028, levels that have no peacetime precedent. Interest payments on accumulated debt are themselves crowding out other budget categories, compressing the fiscal space that governments need to manage shocks or fund productive investment.

The dynamic is self-reinforcing in a troubling direction. Higher defense outlays financed by deficit issuance put upward pressure on bond yields. Higher yields raise the cost of servicing existing debt. Rising debt service, in turn, competes directly with health, education, and infrastructure for budget allocation. The IMF's own modelling confirms that a one percentage point increase in interest expenditure relative to potential GDP reduces other spending categories over subsequent years.

For citizens, the practical consequences are tangible. Social spending falls in wartime defense booms. Inflation rises as defense procurement stimulates demand without proportionate civilian output. Central banks respond by maintaining elevated interest rates, which feeds through into mortgage costs, business borrowing, and consumer credit conditions.

Europe as the Sharpest Case Study

Germany provides a useful illustration. Having partially loosened its constitutional debt brake, Germany's fiscal expansion is heavily weighted toward defense and infrastructure rather than direct consumer support or productivity-enhancing civilian investment. The near-term output effect may appear solid, but the composition of spending matters. Defense procurement does not build schools, improve healthcare access, or reduce the structural impediments to private sector productivity growth.

For smaller NATO members, the pressure is more acute. Countries such as Estonia, Latvia, and Lithuania each spending under USD 4 billion in absolute terms but committing a high share of national resources face the same crowding-out pressures with narrower revenue bases and more limited debt capacity. Most are experiencing subdued growth and have limited room to absorb sustained fiscal expansion without structural consequences.

The United States: Scale, Deficits, and Industrial Primacy

The United States remains the world's largest defense spender, accounting for roughly 37% of global military expenditure. At approximately USD 997 billion in 2025, the US defense budget crossed the symbolic trillion-dollar threshold for the first time, driven by procurement modernization, nuclear deterrence investment, and Indo-Pacific posture adjustments.

The fiscal implications carry particular weight at this scale. The US federal deficit already exceeds 6% of GDP, and public debt stands above 120% of GDP. Defense expansion financed through deficit spending adds to a trajectory that credit markets are increasingly scrutinizing, reflected in sovereign outlook adjustments by major rating agencies in 2025.

For capital markets, the US presents a dual signal. Its defense industrial base, anchored by primes such as Lockheed Martin, RTX, and Northrop Grumman, commands unmatched order visibility through multi-year procurement contracts. Yet sustained deficit financing is contributing to yield curve steepening that institutional investors must price into duration strategies.

The Policy Design Question

The IMF's analysis is careful to note that spending outcomes are not uniform. Defense spending multipliers vary considerably depending on how spending is sustained, how it is financed, how much equipment is sourced domestically versus imported, and whether institutional frameworks can contain the resulting fiscal pressures. Countries that finance military buildups through revenue measures rather than deficit expansion, and that direct procurement toward domestically produced goods, extract more economic value with less long-term debt accumulation.

The report also draws a clear distinction between the macroeconomics of peacetime rearmament and wartime spending. Wartime booms carry substantially higher fiscal costs, with exchange rate depreciation, reserve losses, and inflation compounding the direct budgetary burden. Countries in or adjacent to active conflict face a structurally different risk profile from those undertaking precautionary capacity building.

The Structural Implication for Capital Markets

Rising defense budgets carry real capital market relevance. Sovereign debt issuance is set to increase across NATO member states over the next decade as governments fund the gap between existing revenue capacity and the 5% of GDP target set for 2035. This will affect yield curves, particularly in countries where fiscal credibility is already under scrutiny.

For institutional investors, the sector presents a bifurcated picture. Defense industry equities benefit from exceptional demand visibility and multi-year procurement contracts. Sovereign debt of heavily remilitarizing economies requires more nuanced assessment of fiscal trajectory, debt composition, and the degree to which defense-linked growth translates into durable productivity rather than temporary demand stimulus.

The IMF's framing leaves little ambiguity about the structural tension at work. Rising defense spending can boost near-term demand. It cannot, however, substitute for the investment in human capital, infrastructure, and institutional quality that drives long-term growth potential. Managing that trade-off with precision is the central fiscal policy challenge of the current decade.