The S&P 500 fell 4.36% on Thursday, November 5, 2026, closing at 7,353.73 points in its worst session since April 2025. The Nasdaq Composite lost 5.52% and entered correction territory. The VIX volatility index, the market’s fear gauge, closed at 28.18, its highest since late March.
Selling hit chip stocks and artificial-intelligence infrastructure names hardest, on fears that construction of new US data centers could slow after the midterm elections.
One bad day does not make a crash. But this one lands in a market where several risk factors are stacking up at once, and anyone holding an S&P 500 ETF, perhaps through a regular investment plan, has reason to know what they are.
An index as expensive as the dot-com era
Start with valuations. The Shiller CAPE ratio, which compares the price of the S&P 500 with the average of the past ten years of inflation-adjusted earnings, has been above 40 without interruption since May 2026 and is hovering around 41.
In more than a century and a half of data, that has happened only once before. During the internet bubble the indicator hit a record 44.19 in December 1999. Between March 2000 and October 2002, the S&P 500 lost roughly 49%.
A high CAPE does not say when a decline will come, and the market can stay expensive for a long time. It says the margin of safety is thin, and that a disappointment on earnings or rates hits harder.
Then there is concentration. S&P Dow Jones Indices put the technology sector at 37.9% of the index as of August 31, 2026. The ten largest companies together weighed 39.03% in a reading taken on October 10, led by Nvidia, Apple and Microsoft. Buy the S&P 500 believing you are buying the American economy, and you are largely betting on a handful of big groups tied to artificial intelligence.
Inflation, oil and a Fed back in hiking mode
The second front is interest rates. US inflation rose to 3.7% year over year in September, according to the Bureau of Labor Statistics, driven by an energy index up 20.4% over twelve months.
The Federal Reserve raised rates by 25 basis points on September 16, to a range between 3.75% and 4%, in a unanimous vote and for the first time since July 2023. It left them unchanged on October 28, but two committee members voted for another increase. The September projections pointed to a median rate of 4.1% at the end of 2026, consistent with one more hike. The next meeting is set for December 9.
Oil sits behind the inflation picture. WTI closed the first session of 2026 at USD 57.32 a barrel, then the conflict between the United States and Iran and the blockages in the Strait of Hormuz pushed it beyond USD 100 as early as the end of March. Prices fell about 12% this week on hopes of a de-escalation, but by 6 a.m. Italian time on Friday, November 6, 2026, WTI was climbing again to USD 91.69 after fresh attacks on tankers in the Gulf. ANZ estimates flows through Hormuz remain below 60% of capacity.
Higher rates hurt equities through several channels. They make debt more expensive for households and companies, they hold back investment, and they offer a less risky alternative. The yield on the 10-year Treasury touched 5.36% intraday on October 7, close to its highest levels since 2002. When a US government bond pays more than 5%, the stock market has to offer a great deal to keep investors in.
The debt problem behind artificial intelligence
The third risk is how the artificial-intelligence boom is being financed. Alphabet, Amazon, Meta and Oracle had issued more than USD 228 billion in bonds during 2026 as of October 13, according to LSEG data, more than double the total for all of 2025.
Further down the chain, the companies that build and lease data centers are already paying for market nervousness. The yield on CoreWeave bonds maturing in 2032 touched 15% on October 14, a level associated with distressed debt, and the stock lost 15.5% in a single session.
If the cost of money stays high and investors begin to doubt the returns, some projects may slow. In an index where technology accounts for almost four points out of ten, the backlash would be felt across the whole market.
What history says about crashes
These factors together make a sharp downturn plausible. History helps put it in proportion. Capital Group’s analysis of S&P 500 data from 1954 to 2025 finds that a decline of 20% or more occurs on average about once every six years and lasts 402 days from peak to trough. The last one began in January 2022, as the Fed prepared the rate-hiking cycle that started in March, and took the index down roughly 25% by October.
The figure that matters most is a different one. Again according to Capital Group, every S&P 500 decline of 15% or more since 1929 has been followed by a recovery, and in data through 2023 the average return in the first year after each of those declines was 52%. The catch is that those twelve months start from a point nobody recognizes in real time. Panic sellers risk getting out near the bottom and staying out precisely when the rebound arrives.
Concrete moves for investors based in Italy
Start with an honest check of your own situation. Money you might need in the next two or three years is best kept out of equities, because a 30% decline forces you to sell at the worst possible moment. A cash buffer or short-dated government bonds let you get through the difficult phases without touching your equity investment.
The second point concerns taxes, and many Italian savers discover it too late. For UCITS-compliant ETFs, meaning those that comply with European UCITS rules- as the vast majority of listed ones do, losses realized on a sale count as redditi diversi- (miscellaneous income, the Italian tax category that allows loss offsetting) and can be offset against capital gains of the same type, such as those on stocks, bonds or certificates, within the following four years. Gains on those same ETFs are redditi di capitale- (investment income, an Italian tax category) and cannot absorb previously accumulated losses. Sell an ETF at a loss and buy it back later, and you can be left holding a realized capital loss that is hard to recover.
The third move is to check how much your portfolio really depends on American technology. Anyone holding only an S&P 500 ETF already has nearly 40% of their equity capital concentrated in one sector and a handful of names. Adding exposure to other geographic areas, or to indices built with equal weights across companies, reduces that dependence without leaving the market. For investors in euros, the exchange rate matters too, because an unhedged ETF is exposed both to Wall Street’s performance and to the dollar’s.
The fourth concerns anyone running a regular investment plan. In a downturn, dollar-cost averaging does exactly the job it was designed for, buying more units for the same contribution when prices fall. Suspending it at that moment means giving up its main advantage. Anyone with extra cash available can invest it in tranches rather than all at once, so as not to have to guess the lowest point.
The last is to set yourself a rule before the market tests your nerves. Decide in advance on your target percentages of stocks, bonds and cash, and act only when they drift a few points away from target. That turns a downturn into a rebalancing opportunity rather than a stampede.
Nobody knows whether November 5, 2026 was an isolated accident or the first signal of something bigger. What the data shows is a US market that is expensive, concentrated and exposed to rates and oil. What history shows is that, for anyone with the right horizon and a clear plan, the worst damage is almost always done by the wrong reaction.
| DISCLAIMER The information and considerations contained in this article should not be used as the sole or primary basis for making investment decisions. The reader retains full freedom in their own investment choices and full responsibility for carrying them out, since only they know their own risk tolerance and time horizon. The information contained in this article is provided for informational purposes only, and its publication does not constitute and is not to be considered an offer or solicitation of public savings. |
Editor’s note
This article was originally published in Italian on money.it by Flavia Provenzani on November 08, 2026 as «Crollo di Wall Street, stavolta i campanelli d’allarme sono tanti. Cosa rischia chi investe nell’S&P 500?». It has been translated and adapted for an international audience by the Money.it International desk.
