2026-10-31

Nasdaq's Worst Month Since March 2025: Down 5.3% in October While the Dow Rose 1.7% in a Sharp Reversal From September

Written & reviewed by the TradeSmrt editorial team · 2026-10-31

In this article

What Happened
Why the Dow Rose While the Nasdaq Fell
What to Take Away From This
FAQ
Sources

What Happened

Friday, October 30 was the last trading day of the month, and all three major US indexes closed lower. The Nasdaq Composite dropped 747.72 points (-2.86%) to 25,437.00, the S&P 500 fell 140.32 points (-1.82%) to 7,580.07, and the Dow Jones Industrial Average slid 572.25 points (-1.09%) to 51,770.31. Taken on its own, that single session looks like a broad-based rout. Zoom out to the full month, though, and a very different picture emerges.

Over October as a whole, the Nasdaq Composite fell roughly 5.3% - its worst monthly performance since March 2025. The S&P 500 also slipped about 0.9% for the month. The Dow, by contrast, actually gained roughly 1.7% in October. In the same month that the tech-heavy index was posting a double-digit-adjacent decline, the industrial- and financial-heavy index closed higher. That gap runs in exactly the opposite direction from September, when the Dow fell 3.53% while the AI- and chip-heavy Nasdaq 100 rose 4.58% and the Philadelphia Semiconductor Index (SOX) surged 11.87%. In the span of a single month, the stocks leading the market completely flipped.

The rotation had been building since early October. From October 1 through October 15, the Dow climbed 2.46% while the Nasdaq 100 fell 1.86%, opening a gap of more than four percentage points between the two indexes. Around mid-month, hotter-than-expected inflation data pushed Treasury yields higher, reviving doubts about whether hyperscalers' enormous AI infrastructure spending still makes sense at a higher cost of capital - and the Nasdaq slid to a one-month low. On October 22 alone, the Nasdaq Composite dropped 2.6% in a single session. For the week of October 19-23, the Dow rose 0.41% to 52,215.16 while the Nasdaq Composite fell 0.71%. The small-cap Russell 2000 was the best performer of the four major indexes that same week, up 2.00% - another sign that investor attention was already drifting away from megacap tech.

Then, in the final week of October, Big Tech earnings sealed the trend. Alphabet's (Nasdaq: GOOGL) October 28 report triggered an unrealized mark-to-market loss on its SpaceX stake that crushed EPS, and the stock plunged roughly 12% during the regular session - its worst single day as a public company, wiping out close to $500 billion in market value. That same week, Amazon (Nasdaq: AMZN) reported AWS revenue growth that fell short of expectations, stoking guidance concerns, and Intel (Nasdaq: INTC) delivered a genuine third-quarter beat but followed it with a fourth-quarter guidance shock that sent the stock down more than 20% in a single session. Three distinct pieces of bad news from three different mega-cap names, all landing in the same final week, did most of the work in dragging the Nasdaq's monthly return into negative double-digit territory on a percentage basis.

Why the Dow Rose While the Nasdaq Fell

The core reason lies in how the two indexes are built. The Dow is price-weighted, which gives outsized influence to high-priced financial, industrial and healthcare names, while the Nasdaq is market-cap-weighted, meaning the index lives and dies with its AI and semiconductor megacaps. October's rotation was a textbook illustration of that structural difference. Bank earnings came in broadly solid during the third-quarter reporting season, lifting financial stocks, while healthcare and industrial names absorbed capital flowing out of AI-themed trades. Because those sectors carry disproportionate weight in a price-weighted index like the Dow relative to the S&P 500 or Nasdaq, the same underlying flow of money showed up far more visibly at the index level.

What dragged the Nasdaq down split into two forces. The first was macro. Hotter-than-expected mid-October inflation data pushed yields higher, which immediately raised the question of whether hyperscalers pouring hundreds of billions of dollars into AI infrastructure still makes sense when the cost of capital is rising. Alphabet, Microsoft, Amazon and Meta have together guided to roughly $725 billion in AI-related capital spending this year alone, and the higher rates climb, the more that spending's opportunity cost comes into focus. The second force was company-specific: Alphabet's SpaceX writedown, Amazon's AWS growth deceleration and Intel's guidance shock were each caused by different things, but landing in the same week, they were read collectively as the market's answer - "not yet convinced" - to the season's central question of whether AI capex is actually converting into revenue. Each company had its own story, but investors experienced it as a single week in which confidence in AI megacaps was shaken all at once, and that shock shows up directly in the Nasdaq's monthly number.

One detail worth flagging: the fact that the Nasdaq fell doesn't mean the whole market turned risk-averse. The Russell 2000's relative strength over the same stretch supports a different reading - that money didn't leave the stock market, it simply rotated out of AI megacaps into everything else. Seen that way, October looks less like a market crash and more like a normalization, as capital that had piled into a narrow handful of names over the past year or two spread back out across a wider set of stocks.

What to Take Away From This

Judging "the market" by a single index can mislead you. October was the Nasdaq's worst month since March 2025, yet the Dow actually rose. How exposed your own portfolio is to AI and semiconductor megacaps versus financials, industrials and healthcare determined whether October felt like a rough month or a fine one.
Rotations can reverse direction fast. Semiconductors led the market up 11.87% in September and then became the main drag on the index a month later in October. Assuming a hot theme will keep running in the same direction two months in a row is a dangerous habit.
Bad news clustering in the same week can make isolated problems look like a sector-wide crisis. Alphabet's investment writedown, Amazon's growth slowdown and Intel's guidance miss each had a different root cause, but landing together, they got lumped into a single narrative of distrust toward AI megacaps. Reading each company's actual report, rather than the headline reaction, matters more in weeks like this.
Small-cap strength alongside megacap weakness often signals rotation, not an exodus. When one index falls while another holds up or rises at the same time, that pattern more often points to portfolio rebalancing than to panic selling.
Understanding price-weighting versus market-cap-weighting helps you read headline index numbers correctly. The Dow-Nasdaq-S&P 500 divergence in October wasn't a coincidence - it's a structural consequence of how each index is constructed.

FAQ

Did the whole stock market crash when the Nasdaq fell more than 5%?

No. Over the same stretch, the Dow Jones Industrial Average actually rose about 1.7%, and the small-cap Russell 2000 held up relatively well too. October's weakness was a selective sell-off concentrated in AI and semiconductor megacaps, not a broad, even decline across the entire market.

Does this rotation mean the AI investment boom is over?

It's too early to draw that conclusion. Alphabet, Microsoft, Amazon and Meta have kept their combined AI-related capex plans for the year at roughly $725 billion. October's selling looks less like a demand to stop spending and more like pressure on these companies to prove that spending is actually converting into revenue. That said, if rates keep climbing or another earnings season brings similar disappointments, the rotation could run longer.

Did the Dow only rise because financial stocks carry more weight in it?

Weighting is part of the story, but not all of it. Bank earnings came in broadly strong during the third-quarter reporting season, and healthcare and industrial names also rose as they absorbed capital leaving AI-themed trades. Because the Dow's price-weighted structure reflects price moves in those sectors more directly than a market-cap-weighted index does, the same underlying flow of money showed up more clearly in the Dow's monthly return.

Sources

This article is an original synthesis and analysis based on the reporting below, not a reproduction of the original articles. Please check the source articles directly for the most current figures.

⚠️ This article is for informational purposes only and is not investment advice. Market conditions change constantly, so always verify the latest data before making any investment decisions.