US stocks are having a strong year in 2026. The S&P 500, Dow Jones Industrial Average and Nasdaq Composite are all up by double digits so far this year, showing that investors remain confident in the stock market.
The rally could become a rare winning streak. If the positive market trend continues, all three major indexes could finish 2026 with their fourth straight year of double-digit annual returns, according to The Motley Fool. This would be the first such streak since the period before the dot-com bubble burst in 2000. But the market's gains have not been smooth. Several individual stocks have seen sharp ups and downs during the year. The overall market's strength has also been driven heavily by a relatively small group of megacap companies.
S&P 500 CAPE ratio
This has raised questions about how long the rally can continue. While strong stock market gains can continue for a long time, some valuation measures suggest that US stocks have become extremely expensive.
One major warning sign investors are watching is the S&P 500 Shiller CAPE ratio. CAPE stands for cyclically adjusted price-to-earnings ratio. It compares the S&P 500's price with its average inflation-adjusted earnings over the past 10 years.
CAPE ratio hits 41
{{/usCountry}}One major warning sign investors are watching is the S&P 500 Shiller CAPE ratio. CAPE stands for cyclically adjusted price-to-earnings ratio. It compares the S&P 500's price with its average inflation-adjusted earnings over the past 10 years.
CAPE ratio hits 41
{{/usCountry}}In simple terms, CAPE shows how expensive the stock market is compared with its long-term earnings. A higher CAPE means investors are paying more for each dollar of earnings, while a lower CAPE means stocks look cheaper based on historical standards, according to The Motley Fool. The current CAPE ratio is around 41. That is a very high level by historical standards and is one reason investors are becoming more cautious about the market.
The long-term average CAPE is only about 17. Looking at roughly 150 years of market history, the ratio has averaged around 17, making today's level of about 41 more than twice its historical average. A CAPE above 24 has been relatively unusual. The ratio has crossed the 24 level only six times in market history. It has also stayed above that level for much of the past decade.
A CAPE above 40 is even more unusual. The ratio has crossed 40 only twice in history. The first time happened during the period leading up to the dot-com bubble crash around 2000. The second time is happening now, with the CAPE currently around 41.
Dot-com crash warning
That comparison is worrying, but it does not mean a crash is certain. The current market is at a valuation level that has very little historical precedent. There has been only one previous period when CAPE went above 40, so there is not enough historical evidence to say that today's high CAPE will automatically lead to another dot-com-style crash.
The CAPE ratio cannot predict exactly when a market crash will happen. Valuation indicators can show that stocks look expensive, but they cannot tell investors whether a correction will happen next week, next year or several years from now, according to The Motley Fool.
Stock market correction
Still, history offers an important warning. Very high market valuations have generally been associated with periods when investors should become more careful. The current market is also in a strong bull phase, with high investor optimism. The bigger concern is the size of the market's run-up. When stocks rise sharply and valuations become stretched, the market can become more vulnerable to a correction if investor confidence suddenly weakens.
This does not mean investors need to panic or leave the stock market. The current bull market could continue for years despite the high CAPE ratio. A high valuation alone is not enough to predict the timing of a downturn.
Instead, investors may need to be more selective about where they put their money. Rather than chasing stocks simply because their prices are rising quickly, investors could focus more on companies with strong businesses and long-term growth potential. Quality may become more important if the market turns lower. Companies with durable businesses and stronger long-term prospects may be better positioned to handle a market correction than highly speculative stocks whose prices depend heavily on continued optimism.
The key message from the CAPE ratio is caution, not a crash prediction. With the S&P 500 CAPE at around 41, the market is in historically expensive territory. Investors cannot know when the next correction will come, but the unusually high valuation is a reason to avoid excessive risk and make investment decisions carefully.