When Warren Buffett, widely regarded as one of the greatest investors of all time, described a certain ratio between the stock market and the economy as “probably the best single measure of where valuations stand at any given moment”, the financial community named it the Buffett Indicator.

Today this indicator is frequently cited by analysts and the media as a compass for determining whether the equity market of a given country — in particular the United States — is overinflated or still within a range of reasonable value.

How it is calculated

The Buffett Indicator is the simple division of:

Total market capitalisation of listed companies / Nominal GDP of the country

  • Market capitalisation: the sum of the value of all listed shares (in the US, the Wilshire 5000 is commonly used as the reference index).
  • Nominal GDP: the total value of goods and services produced by a country in a year, measured at current prices.

The result is expressed as a percentage. For example, a ratio of 120% means that the total value of listed companies equals 120% of GDP.

How it is interpreted

Buffett’s underlying idea is intuitive: in a “balanced” market, the value of listed companies should not deviate too significantly from the size of the real economy that sustains them.

Historically, for the United States, the following observations have been made:

  • Below 80–90% → market tending towards undervaluation

  • Between 90% and 115% → valuations in line with the historical average

  • Above 130–150% → possible overvaluation and bubble risk

At the time of writing this article, 13 August 2025, the Buffett Indicator stands at 212.3%.

Very elevated readings do not guarantee an imminent market correction, but they do signal that the market is “running” considerably faster than the real economy.

What it is used for

The Buffett Indicator is not a rapid trading tool, but rather a long-term macro indicator. It is useful for:

  • Gaining a broad sense of how expensive or reasonably priced the market is.
  • Assessing the risk of investing during a phase of collective euphoria.
  • Comparing historical cycles and identifying speculative excesses (such as those seen in 2000 or 2021).

Characteristics and limitations

Like every indicator, this one also has important limitations:

  1. Globalisation: many companies generate a large proportion of their revenues abroad, yet GDP is domestic; this can inflate the ratio.
  2. Interest rates: in periods of very low rates, markets tend to sustain higher multiples, making historical thresholds less reliable.
  3. Inflation: this can temporarily distort both nominal GDP and market capitalisation.
  4. Timing: the indicator can remain “elevated” for years before any significant correction materialises.

In summary

The Buffett Indicator is like a thermometer: it does not tell you when a fever will strike, but it signals whether the body — the market — is running too hot. It is a useful reference point for understanding the broader context in which one is operating, but it does not replace more in-depth analysis of individual securities or sectors.