Tobin's Q
Market value of companies vs. their replacement cost.
The Tobin's Q is 1.82 as of January 1, 2026 — 2 standard deviations above its historical mean of 0.97, a Overvalued reading.
Historical crashes marked on this chart (6)
The dashed red lines flag major US market crashes within this indicator’s history. Here is what happened at each and what followed.
- Kennedy Slide (1962)
- A rapid spring 1962 sell-off (the 'Flash Crash of 1962') wiped roughly 27% off the S&P 500 amid fears over the economy and a clash with steelmakers. Markets stabilized and recovered within about a year.
- 1973–74 oil crisis bear market (1973)
- The OPEC oil embargo, Watergate, and stagflation drove a roughly 48% decline over nearly two years — the worst bear market since the 1930s. Stocks took years to recover in real terms.
- Black Monday (1987)
- On October 19, 1987 the Dow fell 22.6% in a single day — the worst one-day drop in history — driven partly by program trading. The economy avoided recession and markets recovered within two years.
- Dot-com crash (2000)
- The tech bubble burst in March 2000; the Nasdaq lost about 78% by 2002 as internet valuations collapsed. A mild recession followed and tech stocks took roughly 15 years to reclaim their peak.
- Global Financial Crisis (2008)
- The subprime mortgage meltdown and Lehman Brothers' collapse cut the S&P 500 about 57% into March 2009. It triggered the Great Recession, sweeping bailouts, and a decade of near-zero interest rates.
- COVID crash (2020)
- Pandemic lockdowns caused the fastest bear market ever in February–March 2020, a roughly 34% plunge in weeks. Unprecedented Fed and fiscal stimulus sparked a rapid recovery to new highs.
Overview
Tobin's Q — named after Nobel economist James Tobin — compares the market value of US corporate equities to the replacement cost (net worth) of the underlying companies. A value above 1 means the stock market prices companies above what it would cost to rebuild them from scratch, historically a sign of overvaluation; the long-run mean is around 0.75. The ratio climbed above 1.6 at the 2000 dot-com peak and reached fresh extremes in 2021.
How to read it
A Q of 1.0 means the market values companies exactly at what it would cost to replace their assets. The historical mean is around 0.75, so readings near or above 1 are elevated and readings well above 1 (as in 2000 and 2021) have marked major peaks. Higher means more overvalued.
How it's calculated
- Take nonfinancial corporate equities market value from the Fed Z.1 accounts (quarterly).
- Divide by nonfinancial corporate business net worth (replacement-cost basis) from the same release.
- Compare against the long-run mean of ~0.75 with standard-deviation bands.
Criticisms
- Replacement cost is hard to measure, especially for intangible-heavy modern firms.
- Quarterly Z.1 data is released with a lag, so the latest reading is an approximation.
Frequently asked questions
- What is a normal Tobin’s Q ratio?
- The long-run average Tobin’s Q is about 0.75. A value of 1.0 means the market prices companies exactly at their replacement cost; readings well above 1 — as in 2000 and 2021 — signal overvaluation.
- How high was Tobin's Q during past bubbles?
- Tobin's Q rose above 1.6 at the peak of the dot-com bubble in 2000 and reached comparable or higher extremes in 2021, far above its ~0.75 historical mean.
- What does a Tobin’s Q above 1 mean?
- A Q above 1 means investors value companies higher than what it would cost to rebuild them from scratch — in theory that lures new competition and investment until the premium erodes, so persistently high Q suggests overvaluation.