The Shiller CAPE ratio, which calculates the S&P 500's earnings in relation to its price over the past decade, adjusted for inflation, reached 40.91 in July 2026. This is the highest it has been since August 2000, marking a 26-year high. The figure stands out as it surpasses the long-term historical average of around 17, and the median CAPE ratio since 2000 is roughly 27, while over the past 50 years it has averaged about 20. Shiller, is seen by many as a reliable indicator of the stock market's valuation. It smooths out short-term volatility by using a 10-year earnings average, providing a longer-term view of whether the market is overvalued or undervalued.
Historical context
Looking at historical data reveals a pattern: when the CAPE ratio spikes to unusual levels, it has often preceded market downturns. For example, in July 1929, it climbed to 31, a then record high. Just months later, the market crashed, launching a four-year bear market that coincided with the Great Depression. The Roaring '20s had seen soaring stock prices thanks to the Second Industrial Revolution, but the subsequent collapse wiped out enormous gains in a short time. The last time the CAPE ratio rose above 40 was in November 1999, when it hit 44.19 at the height of the dot-com boom. That era was marked by high-flying tech stocks and massive investor optimism, but it eventually led to a three-year bear market from 2000 to 2002 as the bubble burst.
The 1990s boom saw the market deliver annual returns of more than 20% for five years, from 1995 through 1999. However, the high CAPE ratio at that peak served as a warning of overvaluation. Many of the companies driving the boom had little to no earnings, and speculation was rampant. This pattern raises the question of whether the current CAPE surge could follow a similar path, especially with AI-driven growth reshaping corporate earnings and investor sentiment.
Recent market cycles
The CAPE ratio saw another significant rise during the post-pandemic tech boom, peaking at 38.58 in October 2021. This period, from April 2020 to October 2021, was marked by strong demand for tech stocks and a broad-based surge in the market. However, this was followed by a bear market that lasted until 2022. During this downturn, the Nasdaq dropped by about 33%, while the S&P 500 fell around 19%. The crash was fueled by rising interest rates and a shift in investor sentiment toward value stocks and lower-risk assets.
Despite the sharp downturn, markets have since bounced back, with four consecutive years of double-digit gains, including the 10% increase in the S&P 500 in 2026 as of August 3. This recent rally has been largely driven by the artificial intelligence (AI) revolution, which has sparked innovation, increased efficiencies, and boosted corporate profits. Unlike the speculative nature of the 1990s boom, the current market is supported by real earnings growth, which could allow for higher valuations to be sustained for longer periods.
The question now is whether the CAPE ratio's current high level will signal another major market correction. If past trends hold, a downturn could be on the horizon, but the nature of the correction remains uncertain. Will it resemble the three-year dot-com bust or the four-year Great Depression bear market? Or will it be a shorter, sharper decline or a prolonged period of volatility? Experts caution that while history provides useful insights, it is not a perfect predictor. This current cycle is shaped by real economic forces and solid earnings, which may support a more stable market environment.
As the CAPE ratio continues to rise, investors are watching closely. The challenge is balancing optimism about AI-driven growth with the caution that history suggests when valuations rise too high. Understanding the past can help investors prepare for the future, even if it doesn't guarantee they will avoid losses. The key is recognizing trends, staying informed, and making decisions based on sound analysis rather than speculation.