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Methodology
METHODOLOGY · INDICATOR

Valuation

Are markets priced for perfection, or for disappointment?
WEIGHT
30%

WHAT WE MEASURE

Valuation compares current market prices to fundamental measures of economic output and corporate earnings. When prices detach from the underlying reality of what businesses actually produce, a reversion toward fair value becomes increasingly likely. This category aggregates multiple metrics to create a robust picture of whether the market is cheap, fair, or dangerously expensive.

WHY IT MATTERS FOR BUBBLE DETECTION

High valuations are the single best long-term predictor of poor forward returns. Across 124 years of US market history, every major bubble has been preceded by extreme valuations: the 1929 crash, the dot-com collapse, and the 2022 correction all began from elevated starting points. Overvaluation does not tell you when the market will correct, but it tells you the risk/reward is skewed unfavorably.
Each metric is normalized against a 20-year rolling window and scored 0–100 (a score of 70 means more extreme than 70% of historical readings). The Valuation category combines multiple normalized metrics using equal weighting, then contributes 30% of the overall composite score.

KEY METRICS & THRESHOLDS

Shiller CAPE (PE10)
Cyclically Adjusted Price-to-Earnings ratio: divides the S&P 500 price by the 10-year rolling average of real (inflation-adjusted) earnings. Developed by Nobel laureate Robert Shiller, it smooths out business-cycle volatility in earnings.
SOURCE: Robert J. Shiller, Yale University (shillerdata.com)
Undervalued
< 15
Fair Value
15 – 22
Elevated
22 – 30
High
30 – 37
Extreme
> 37
Buffett Indicator
Total US stock market capitalisation divided by nominal GDP. Warren Buffett described it in 2001 as "the best single measure of where valuations stand at any given moment." It captures how much of the real economy is priced into equities.
SOURCE: Warren Buffett, Fortune Magazine (2001); Wilshire 5000 / BEA GDP
Undervalued
< 75%
Fair Value
75 – 100%
Elevated
100 – 135%
High
135 – 165%
Extreme
> 165%
Price-to-Sales (P/S)
Market capitalisation divided by aggregate revenues of S&P 500 companies. Unlike P/E, it cannot be distorted by earnings manipulation or temporarily depressed earnings during recessions. A reliable cross-cycle measure.
SOURCE: S&P Global, Bloomberg Financial Data
Cheap
< 1.2
Fair
1.2 – 1.8
Rich
1.8 – 2.4
Very Rich
2.4 – 3.0
Extreme
> 3.0

HISTORICAL EPISODES

Sep 1929
Great Crash
SIGNAL
Shiller CAPE ~32.5
OUTCOME
Dow Jones fell 89% by 1932
Mar 2000
Dot-com Peak
SIGNAL
Shiller CAPE 44.2, an all-time high at the time
OUTCOME
S&P 500 fell 49% over 2000–2002
Oct 2007
Pre-GFC Peak
SIGNAL
CAPE ~27, Buffett Indicator ~110%
OUTCOME
S&P 500 fell 57% over 2007–2009
Jan 2022
Post-COVID Peak
SIGNAL
CAPE ~40, Buffett Indicator ~210% (all-time high)
OUTCOME
S&P 500 fell 25% in 2022 bear market

HOW TO INTERPRET THE SCORE

Low Risk
0 – 30
Valuations are below or near historical averages. Risk/reward is favorable.
Moderate
30 – 55
Moderately elevated. Not alarming but warrants monitoring.
Elevated
55 – 75
Significantly above historical norms. Forward returns are likely muted.
Extreme
75 – 100
Historically rare territory. Major corrections have originated from these levels.

ACADEMIC & INDUSTRY SOURCES

[1]
Shiller, R.J.: Irrational Exuberance2000, 2015
[2]
Shiller, R.J. & Campbell, J.Y.: Stock Prices, Earnings and Expected Dividends1988
[3]
Buffett, W.: Buy American. I Am. (Fortune)2001
[4]
Hussman, J.: Weekly Market Comment (HussmanFunds.com)2000–present