Starting point: the Buffett Indicator for the U.S. equity market. As of December 2025, it reads 184% — nearly twice the size of the economy. The historical fair value zone for the U.S. sits at 100–120%. At the dot-com peak, it reached ~140%. The gap between where the market is and where it should be is the largest it has ever been. What follows is an attempt to reverse-engineer the economic conditions required to close that gap through growth alone — without a correction.
Gap = 184%÷ 120% = 1.53×
GDP must outgrow equities by 53% cumulatively to normalize
Click any scenario to expand. Bar = years to reach 120% Buffett Indicator. ∞ = ratio diverges.
04 — Decomposition
Required GDP growth vs. actual trajectory
3.5–4.5%
Required real GDP growth per year for 10–12 years
to close the gap with zero equity market appreciation
2025 Full Year (BEA)
2.2%
Post-2010 avg: ~2.0%
1.6–2.0× below required
IMF U.S. Forecast 2026
2.4%
WEO Jan 2026
1.5–1.9× below required
Last Decade Above 3.5%
1960s
60+ years ago
No modern precedent
1.5–2.3×
Required growth exceeds every major institutional forecast. Even the most optimistic projections fall short by 50%+.
05 — Productivity Constraint
The AI productivity gap: required vs. projected
Required to justify valuations
3–4%
Labor productivity growth / year sustained for a decade
vs.
IMF & Academic consensus
0.07–0.8%
Range of projected AI-driven productivity gains / year
Source
TFP Gain
Horizon
Annual Equiv.
Acemoglu (2025)
0.7%
10 yr
~0.07%
IMF WP/25/76 — Low
0.9%
5 yr
~0.18%
IMF WP/25/76 — High
2.4%
10 yr
~0.24%
IMF WEO — AI medium-term
—
annual
0.1–0.8%
Goldman Sachs (2023)
7%
10 yr
~0.7%
1995–2004 IT Boom (actual)
—
decade
~2.5%
Required by valuation math
—
annual
3–4%
4–43×
The required productivity growth is 4× the most optimistic IMF scenario and 43× the Acemoglu conservative estimate.
Sources: IMF WP/25/67, WP/25/76 (Apr 2025), WEO Jan 2026, Acemoglu (2025), Goldman Sachs (2023), BLS
06 — Simultaneous Requirements
All conditions needed, at once
Condition
Required
Baseline
Multiple
Real GDP growth (10yr avg)
3.5–4.5%
2.0%
1.8–2.3×
S&P 500 EPS growth (10yr avg)
10–12%
6.5%
1.5–1.8×
AI revenue growth (sustained)
20–30%
decays <3yr
∞
Recessions in 10yr window
0
~1.3
P ≈ 15–20%
Labor productivity growth
3–4%
1.2%
2.5–3.3×
AI-driven TFP (vs. IMF high)
3–4%
0.24%
12–17×
07 — Inflation Path
Can inflation close the gap instead?
Low Inflation (2–3%)
18–22×
Historical avg P/E GDP grows slowly, multiples expand
High Inflation (5–7%)
7–10×
1970s avg P/E GDP rises, equities repriced down
At 5.5% inflation + 2% real: T = 5.8 yr on paper
But sustained 5%+ inflation → P/E compresses ~20× to ~10× → 50% numerator destruction
Ratio normalizes through a crash, not growth
08 — Calculator
Test your own assumptions
Convergence Scenario Builder
Real GDP Growth
2.0%
Inflation
2.5%
Equity Market Growth
3.0%
09 — Result
Joint probability: no historical precedent
At current prices, the U.S. equity market requires 3.5–4.5% real GDP growth for a decade,
earnings growth at 1.7× the historical rate,
productivity gains 4–43× above IMF and Academia projections,
zero recessions across a 10-year window,
and AI revenues compounding at 20–30% indefinitely —
all simultaneously.