The Big Macro Force That's Been Driving Stocks Higher for Years

What It Covers

Minneapolis Fed economist Jonathan Heathcote presents research explaining why US stock market valuations have remained persistently elevated since 1980. The paper argues that declining labor share of corporate output and low capital expenditure relative to earnings have driven free cash flow growth, making high price-to-earnings ratios less alarming than they appear.

Key Questions Answered

• •Free Cash Flow vs. Earnings Ratio: Price-to-free-cash-flow ratios show no long-term upward drift since 1952, unlike the Shiller CAPE. The ratio in 1980 and 2022 sits at roughly the same historical average. Investors focused solely on price-to-earnings ratios may be misreading market overvaluation by ignoring how much cash actually returns to shareholders after all expenditures.
• •Labor Share Decline: Corporate sector wages and salaries fell approximately 8 percentage points as a share of GDP between 1980 and 2022. This shift from labor to capital owners directly inflated corporate earnings and free cash flow. Investors should track labor share trends as a leading indicator of future corporate profit margins and equity valuations.
• •Investment Suppression Amplified Returns: Big tech firms generated outsized free cash flow by producing high earnings with minimal capital expenditure — the opposite of capital-intensive industries like oil. This structural dynamic, not speculative excess, explains elevated valuations for roughly 50 firms that account for the majority of total US stock market value growth.
• •AI Capex Shift as Valuation Risk: The current AI-driven investment boom by major tech firms represents a structural reversal of the low-capex model that sustained high free cash flow. If capital expenditure remains elevated without proportional revenue gains, price-to-free-cash-flow ratios will compress. Investors should monitor quarterly free cash flow data, not just earnings, for early warning signals.
• •Dot-Com Era as Irrational Benchmark: The 2000 dot-com peak is the clearest historical example of valuations detaching from free cash flow fundamentals — prices were sky-high while cash flow was weak. By contrast, current large-cap tech valuations are grounded in actual present cash generation, not future earnings projections, making today's environment structurally different from that bubble.