Could the Stock Market Crash? A Signal Seen Six Times in 155 Years
Bharatmorning.com – Could the stock market crash right now? That question has gained urgency as an indicator dating back to 1871 flashes a reading investors have witnessed only six times across more than 155 years of American equity history. The cyclically adjusted price-to-earnings ratio — the CAPE ratio — currently prints at 41.1, more than double its long-run average of approximately 17.8. In practical terms, today’s share prices embed a premium that the historical record says is extraordinarily rare.
How the CAPE Ratio Differs from a Standard Multiple
A conventional P/E ratio captures earnings from a single fiscal year, making it vulnerable to one unusually strong or weak quarter. The CAPE ratio, by contrast, averages inflation-adjusted corporate profits over a rolling ten-year window. That smoothing strips out cyclical noise and gives analysts a longer-horizon gauge of whether equities look expensive or cheap relative to the underlying economy.
Sustained readings above 30 are the threshold that matters. Across the full dataset reaching into the early 1870s, the ratio has held above that level for multiple consecutive months on only six occasions during major bull-market phases. The present rally marks the sixth.
What Followed the Previous Five Episodes
The first and most devastating episode arrived in the late 1920s. Two decades of speculative excess had driven valuations to extremes before the 1929 crash wiped out fortunes in days. The ensuing bear market bled into the early 1930s, deepening the damage of the Great Depression.
The second window stretched from roughly 1997 through 2001. The CAPE ratio peaked near 44 during that stretch, and technology shares continued climbing even after prices had become grotesquely stretched. When the dot-com bubble finally burst, the Nasdaq Composite fell approximately 77 percent from peak to trough, erasing trillions in market capitalization.
The third and fourth episodes bracketed the pandemic shock. Within the first two months of 2020, global lockdowns plunged the S&P 500 into a bear market of unprecedented speed. The fifth episode ran from 2020 into 2022: central banks injected unprecedented monetary support while holding policy rates near zero, fueling a rapid equity recovery. That recovery collided with inflation that surged to around 9 percent. The Federal Reserve responded with aggressive rate hikes, and the S&P 500 slid into another bear market in 2022, with high-growth technology names absorbing the heaviest selling as investors recalibrated discount rates.
Current Risks: Monetary Policy and the AI Buildout
One variable that could accelerate a repricing event is the direction of monetary policy. With Kevin Warsh now expected to lead the Federal Reserve, some participants fear a more hawkish tilt than current consensus pricing assumes. Higher borrowing costs would raise the price of capital at precisely the moment American corporations are committing hundreds of billions of dollars to artificial-intelligence infrastructure — data centers, GPU clusters, networking hardware, advanced memory, and power-generation capacity.
The AI buildout is capital-intensive by design. If the cost of debt rises, firms may throttle back on those expenditures. A deceleration in AI-related capex would remove one of the principal pillars propping up today’s equity rally, and investors could begin questioning whether the premium embedded in current share prices is warranted if forward growth prospects soften. The consequence would be a sharp repricing: holders of overpaid equities would demand lower prices, compressing multiples across the board.
A high CAPE reading does not deliver a countdown. It signals a shift in the risk-reward calculus: forward expected returns compress, and the probability of a meaningful multi-year drawdown rises relative to periods when the ratio hovers near its historical mean.
Treating a stretched CAPE as a precise crash timer would be a category error. The dot-com era proved that valuations can remain grotesquely elevated for years while prices keep rising, only to collapse abruptly when sentiment finally reverses. What the metric communicates is not timing but probability — and that distinction matters for portfolio construction.
Frequently Asked Questions
Is the CAPE ratio a reliable crash predictor? It is not a timing tool. Historically, sustained readings above 30 have preceded major drawdowns, but the lag between the signal and the event has ranged from months to years. Think of it as a risk gauge, not a calendar.
What should long-horizon investors do when the CAPE sits above 30? The historical record argues for broader diversification, disciplined position sizing, and a willingness to tolerate volatility without abandoning a long-term allocation. It does not argue for exiting equities entirely.
How does the current AI spending cycle interact with valuation risk? If monetary policy tightens faster than expected, the cost of financing AI infrastructure rises. A slowdown in that capex would weaken one of the key growth narratives underpinning today’s premium multiples, increasing the odds of a repricing event.