October brought a lot of carnage in tech stocks, but you might not guess that from the S&P 500's performance.
The S&P 500 SPX declined 0.9% for October, even though 72% of stocks in the large-cap benchmark index were up for the month.
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The S&P 500 is about 40% concentrated in its largest 10 stocks by market capitalization. And while the index was down, the Invesco S&P 500 Equal Weight ETF RSP was up 5% for October — reflecting the underlying strength in stocks, even as many of the largest technology companies have fared poorly as investors question the AI infrastructure build-out. And as you can see below on the list of the month's worst performers, even non-IT companies, such as Caterpillar CAT, were hit hard during what might be a temporary backlash against the rapid pace of data-center construction.
Among the largest 10 components of the S&P 500, Nvidia NVDA (the largest of all) was down 10.4% for October, while Alphabet GOOGL GOOG dropped 18.7%, Amazon.com AMZN declined 3.5%, Broadcom AVGO was down 7.1%, Meta Platforms META was down 15.2% and Micron Technology MU fell 16.9%. (All price changes in this article exclude dividends.)
Read: The rest of the market is leaving Big Tech behind after a historic comeback
See: Alphabet's stock just triggered a 'death cross.' Could the worst of the selloff be over?
Also: Amazon's stock drops — even in the face of a bold new cloud forecast
Rounding out the largest 10 components of the index, Apple AAPL rose 3.5% for October through, while Microsoft MSFT was up 1.8% for the month, Tesla TSLA was up 12.7% and Eli Lilly LLY soared 22.5%.
Read: The major reason Microsoft's stock is heading higher after earnings
One more Big Tech tidbit: SpaceX SPCX is not yet a component of the S&P 500; it's stock declined 10.7% during October.
The S&P 500's best October performers
These were the 20 best-performing stocks in the S&P 500 for October:
Company
October price change
2026 price change
Accenture ACN
40.8%
-3.7%
PTC PTC
39.4%
12.2%
Hasbro HAS
35.8%
45.2%
Equifax EFX
34.5%
-14.9%
Roper Technologies ROP
33.5%
4.8%
Crown Castle CCI
33.1%
-0.2%
Gen Digital GEN
32.3%
7.1%
APA APA
27.2%
115.9%
Dow DOW
26.0%
48.4%
Lockheed Martin LMT
25.1%
31.7%
Pentair PNR
25.0%
-36.4%
Tyler Technologies TYL
23.8%
-13.1%
Intuit INTU
23.7%
-48.5%
ConocoPhillips COP
23.1%
64.5%
GoDaddy GDDY
22.8%
-5.5%
Gartner IT
22.6%
-9.3%
Eli Lilly LLY
22.5%
31.9%
Regeneron Pharmaceuticals REGN
22.4%
20.2%
FactSet Research Systems FDS
22.1%
13.6%
Cboe Global Markets CBOE
21.9%
33.7%
Source: FactSet
October's worst S&P 500 performers
These 20 components of the S&P 500 fell the most for October:
Company
October price change
2026 price change
Intel INTC
-45.3%
78.2%
Reddit RDDT
-35.6%
-60.1%
Sandisk SNDK
-33.9%
384.8%
Teradyne TER
-31.6%
41.7%
Seagate Technology Holdings STX
-30.1%
134.1%
Twilio TWLO
-29.9%
44.1%
Lam Research LRCX
-27.2%
39.7%
Coherent COHR
-26.9%
14.0%
Bloom Energy BE
-26.6%
133.8%
Marvell Technology MRVL
-25.7%
131.1%
Comfort Systems USA FIX
-25.5%
32.1%
Robinhood Markets HOOD
-24.5%
-24.9%
F5 FFIV
-24.0%
32.5%
Fortinet FTNT
-23.9%
71.4%
Applied Materials AMAT
-23.7%
51.8%
Caterpillar CAT
-23.2%
8.7%
Skydance SKYD
-23.0%
-40.7%
Coinbase Global COIN
-23.0%
-36.5%
ServiceNow NOW
-21.6%
-31.4%
Flex FLEX
-21.4%
43.1%
Source: FactSet
Intel INTC was the S&P 500's worst performer during October, with its shares plunging after the company disappointed investors with its revenue forecast .
More: After Intel's historic stock drop, analysts say there's no reason to buy the dip
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