Quarterly Review and Outlook Third Quarter 2025

Idle Plants, AI, and High Tariffs

The combined effects of declining capacity utilization in the United States and globally, the inherently deflationary power of artificial intelligence (AI), the Federal Reserve’s deliberate monetary restraint, and the liquidity-draining impact of tariffs will serve to impede economic growth and decrease inflation through 2025 and beyond.

Idle Plants

Contrary to the current conventional wisdom, plant capacity utilization has declined again this year in the U.S., the EU, and China. This trend has persisted since the 2021–22 period. A weighted index of these economies, plus Japan and the U.K., reflects this decline (Table 1). Many factories, refineries, mines, and mills now sit with more idle capacity or operate at low utilization rates.

table 1

Construction of homes, offices, apartments, and other structures have also contracted. The goods-producing sector is not as large of a contributor to economic activity as it was in the past, but it still plays a critical role. As of August 2025, goods-producing employment was less than 20% the size of private service-providing employment. However, the workweek in the goods-producing sector was 20% longer, and average hourly earnings were 2.8% higher. This resulted in a far greater contribution to personal income per person in the goods-producing sector than in the private service sector. Thus, the historical and theoretical work on plant capacity utilization as a precursor of economic cycles remains highly relevant in this new era.

Capacity Utilization

Economists have long tracked capacity utilization. Thomas Malthus (1766-1834) was among the first to write about overcapacity and its effects, while later economists Wesley Clair Mitchell (1874-1948) and Arthur F. Burns (1904- 1987) developed data series linking capacity utilization to business cycles in their influential book Measuring Business Cycles, (published in 1946).

Polish-born economist Michał Kalecki (1899–1970) was arguably the first to place capacity utilization at the center of business cycle theory. Cambridge Economist Joan Robinson (1903–1983) argued that, in free market economies, investment is driven by expected demand. This makes capacity utilization—not just technology or saving—central to growth dynamics. She expanded this concept into growth models, which were further developed by others. This is the critical reason why tax incentives for physical investment may be slow to have an effect, and why a capital expenditure boom for 2026 is unlikely. This is true even with the favorable new expensing features in the tax code.

Drawing from these and later contributors, economists generally agree that persistently low levels of capacity utilization should raise concern about the sustainability of the business cycle for several reasons:

  1. Reduced productivity growth - equipment and infrastructure that sit idle contribute nothing to output, slowing the growth of overall efficiency.
  2. An impediment to capital formation - firms with idle machinery and buildings do not expand capacity. This depresses new investment spending. Sunk costs of underutilized assets play a critical role in this decision.
  3. Labor market pressures - idle plants often lead to layoffs, reduced hours, and weaker demand for local suppliers, amplifying cyclical downturns.
  4. Profit compression - excess capacity prompts firms to engage in price-cutting to cover fixed costs, which squeezes profits.
  5. Financial stress - companies struggle to service debt tied to unused assets, which raises the risk of bankruptcies and nonperforming loans in the banking system.
  6. Downward price pressures - when demand is weak relative to potential supply, firms cut prices or restrain wage growth, pushing the economy toward disinflation or deflation.