S&P 500: The Winners and Losers of October 2026

S&P 500: The Winners and Losers of October 2026

October 2026 produced one of the widest gaps between the best and worst performers of any month this year, with roughly 86 percentage points separating the top stock from the bottom one. The month’s three winners rose on a takeover bid and two earnings reports that forced investors to rethink how AI affects software and consumer brands. The three losers all reported revenue growth, and two of them beat expectations outright, yet fell anyway because the market decided their future looked less certain than their share prices had assumed. Intel is the clearest illustration of how quickly sentiment turned. It was among the S&P 500’s strongest performers in September, rising roughly 35%, and then became the index’s worst performer in October. In this article, we break down the top winners and losers in the S&P 500 for October 2026 and examine the key drivers behind their stock movements.

Top S&P 500 Performers in October

Among the top performers were Accenture (ACN), PTC (PTC), and Hasbro (HAS). Here’s a closer look at why each of these stocks stood out:

Accenture ($ACN) +40.8%

Accenture, one of the world’s largest professional services and consulting firms, rose nearly 41% in October after a fiscal year-end report that directly challenged the idea that generative AI would erode demand for human-intensive consulting work.

The setup mattered. Accenture had fallen sharply in June on exactly that fear and entered October around $183, having drifted lower through September despite expanding its relationship with Anthropic mid-month. Expectations were low.

On October 1, Accenture reported fourth-quarter revenue of $18.68 billion, up 6% in dollars and 7% in local currency, above its own guided range of $17.75 billion to $18.40 billion. New bookings reached $22.17 billion for a book-to-bill ratio of 1.2, and GAAP diluted earnings per share rose 46% to $3.29. For the full fiscal year, revenue was $74.18 billion and the company returned a record $11.5 billion to shareholders.

The forward outlook was the decisive part. Management guided fiscal 2027 to local-currency revenue growth of 3% to 6%, GAAP diluted EPS of $14.39 to $14.81, and at least $9.5 billion returned to shareholders. That guidance told investors that clients were hiring consultants to deploy AI rather than cutting them. Accenture closed up roughly 16% on October 1 on about 29 million shares against 10.5 million the prior session, and the move lifted peers across the IT services sector, confirming the market read it as a signal about the whole industry rather than one company. The stock finished the month near $258.

PTC ($PTC) +39.4%

PTC, an industrial software company whose tools manufacturers use to design, engineer, and manage complex physical products, rose roughly 39% in October for a reason entirely unrelated to its own operating performance. It agreed to be acquired.

PTC had fallen about 8% in September to close at $140.30, which meant the premium was calculated from an already depressed base. On October 5, Schneider Electric and PTC announced a definitive agreement under which Schneider would acquire PTC for $205 per share in cash. The offer valued PTC’s equity at approximately $22.6 billion with an implied enterprise value of $23.7 billion, representing a 42.3% premium to the prior closing price and a 46.1% premium to the preceding 30-day volume-weighted average price. Both boards approved unanimously, with closing expected by the third quarter of 2027 subject to shareholder approval and regulatory clearances.

The strategic logic was about data. Schneider already owned industrial software covering how plants and energy systems operate. PTC adds the upstream layer of how products get designed and built, and connecting those two datasets is what industrial AI systems need to produce real efficiency gains.

PTC jumped about 33.5% on October 5 to $192.26 on roughly 29.6 million shares, then traded below the offer price for the rest of the month, ending near $195.54. That remaining gap of about 4.6% is a merger-arbitrage spread, compensating holders for the time value of money and for deal risk across a closing timeline that runs into 2027. PTC has since said it will suspend regular earnings calls and its usual guidance framework, which makes conventional standalone valuation work largely beside the point while the deal is pending.

Hasbro ($HAS) +35.8%

Hasbro, the games, toy, and entertainment company behind Magic: The Gathering, Monopoly, and Dungeons & Dragons, rose nearly 36% in October after a quarter that showed how thoroughly its earnings mix has shifted away from physical toys.

On October 20, Hasbro reported third-quarter revenue up 15% to $1.6 billion, with adjusted operating profit up 52% to $541 million and adjusted diluted earnings per share of $2.90 against a consensus near $1.85. The Wizards of the Coast and Digital Gaming segment grew 31%, led by Magic: The Gathering revenue rising 34% to $616 million, the first time the game has exceeded $600 million in a quarter. That segment ran a 49% operating margin, which explains why mix matters so much to consolidated earnings power.

Management raised full-year guidance across the board, lifting constant-currency revenue growth to 7% to 9% from 5% to 7%, adjusted EBITDA to $1.575 billion to $1.625 billion from $1.45 billion to $1.50 billion, and doubling the share repurchase target to $400 million.

Two caveats deserve mention. The quarter included roughly $55 million of tariff refunds, which should not be treated as recurring, and about $40 million of Magic sales shifted into the third quarter from the fourth because of early shipments. Even adjusting for both, adjusted operating profit grew by more than a third. Hasbro closed up roughly 11% on the day and continued climbing to finish October near $119. The company’s own release flags the growing concentration of sales and profits in Magic as a business risk.

Worst S&P 500 Performers in October

Among the biggest decliners in the S&P 500 for October 2026 were Intel (INTC), Reddit (RDDT), and Sandisk (SNDK). What connects them is that all three grew revenue, and none of the declines was caused by a bad quarter in the conventional sense. Here’s a closer look at what drove their underperformance.

Intel ($INTC) -45.3%

Intel, the semiconductor company that designs and manufactures CPUs and is building a contract chipmaking business, lost roughly 45% in October, the steepest decline in the index. The severity owed as much to where the stock started as to what the company reported.

Intel had rallied roughly 35% in September, from $88.97 to $120.23, on optimism about AI-related CPU demand, pricing power, and its manufacturing turnaround. That rally set an unusually high bar.

On October 29, Intel reported third-quarter revenue of $16.5 billion, up 21% year over year, with GAAP earnings per share of $0.60 and non-GAAP EPS of $0.52. Revenue, gross margin, and earnings all exceeded guidance, and the CFO noted the strongest data center revenue growth in 15 years. The problem was the outlook. Management guided fourth-quarter revenue to $15.0 billion to $16.0 billion with non-GAAP EPS of $0.25, more than $1 billion below the midpoint of market expectations, and said it expected the PC slowdown to continue at least through the first half of next year.

The underlying tension was awkward. Intel’s data center products were supply-constrained precisely when demand was strongest, while its PC exposure faced one of the weakest demand environments in years, and higher memory prices were raising system costs. Capital spending to expand manufacturing capacity remained heavy with no positive cash flow expected for the year. Intel fell close to 29% on October 30 on roughly 455 million shares, erasing more than $140 billion in market value, and its five-year credit default swap spread widened to a record. Short interest around mid-October was about 3% of float and falling, which argues against a squeeze unwind explanation. This was an expectations reset, amplified by a crowded turnaround narrative and a broad technology selloff the same day.

Reddit ($RDDT) -35.6%

Reddit, the social platform that monetizes community discussion through advertising, fell nearly 36% in October despite reporting one of the strongest quarters of any company in the index.

On October 29, Reddit reported third-quarter revenue of $895 million, up 53% year over year, with gross margin of 91.5%, net income of $283 million, adjusted EBITDA of $402 million, and free cash flow of $363 million. Daily active uniques reached 130.3 million, up 12%.

The problem was buried in the user numbers and the risk disclosures. U.S. daily active uniques fell 2% year over year, and the company stated that the evolution of third-party search, specifically the growth of AI-generated summaries and overviews, had created increased volatility in referral traffic. Reddit warned that AI-generated answers reduce the probability that a user clicks through to Reddit at all, which in turn reduces referral traffic, user growth, and advertising reach. It cautioned that daily active uniques could fall by a low-double-digit percentage in the fourth quarter if the trend persisted, with more than one million average weekly referrals reportedly disappearing during October.

The stock fell roughly 29% in a single session on October 30, its steepest one-day decline, on about 33.7 million shares. The market was not repricing current earnings. It was repricing distribution risk. A high-margin advertising platform can justify a premium multiple only while traffic growth stays durable and cheap, and the question investors now face is who controls the user relationship when AI systems answer queries using Reddit-derived content. The mitigating detail is that logged-in and app users, who engage and monetize better than search visitors, grew sequentially in both the U.S. and internationally.

Sandisk ($SNDK) -33.9%

Sandisk, the flash storage company serving data center, enterprise, and consumer markets, fell roughly 34% in October after reporting what was by any normal standard an exceptional quarter.

On October 29, Sandisk reported fiscal first-quarter revenue of $11.0 billion, up 23% sequentially, GAAP net income of $8.1 billion, and non-GAAP diluted earnings per share of $49.51. The company returned $5.0 billion through buybacks during the quarter and announced an eight-for-one forward stock split effective in November. Guidance for the following quarter called for revenue of $12.2 billion to $12.6 billion.

The selloff was about the second derivative rather than the current quarter. On October 30, competitor Kioxia signaled that the extraordinary run-up in NAND flash pricing was decelerating, with its average selling prices rising in the mid-20% range in the September quarter against roughly 70% in the quarter before, and its own forward guidance pointing to much flatter sequential gains. Memory stocks trade less on the level of current earnings than on the expected direction and acceleration of pricing six to twelve months out, so Sandisk could post 85% gross margins and still fall once investors concluded the best rate of improvement had passed.

Positioning amplified it. Sandisk had risen roughly 13% in September alone and was one of the year’s largest AI and memory beneficiaries, so the share price already embedded exceptional pricing conditions. Short interest was only around 3.3% of float, which rules out a squeeze reversal as the explanation. The decline also landed during a broad AI technology selloff on October 30, the same session that hit Intel and Reddit, as investors questioned hyperscaler capital spending more generally.

What the Month Really Said

October’s dispersion came down to a single distinction: the winners received information that raised expected future cash flows, or in PTC’s case fixed them at a contractual price, while the losers received information that cast doubt on how long their existing performance could continue.

That distinction is worth sitting with, because the usual shorthand of good earnings versus bad earnings does not apply here. Intel beat its own guidance on revenue, margin, and earnings. Reddit grew revenue 53% with a 91.5% gross margin. Sandisk grew revenue 23% sequentially and earned $8.1 billion in a quarter. All three fell between 34% and 45%. What they had in common was that each entered October priced for continued acceleration, and each disclosed something suggesting acceleration would slow, whether from PC demand, AI search intermediation, or NAND pricing.

The winners show the same mechanism running the other way. Accenture and Hasbro both entered the month depressed, Accenture because investors feared AI would destroy consulting demand and Hasbro because its recovery was underappreciated. When results contradicted those assumptions, the re-rating was violent in the opposite direction. There is also something telling in the fact that a French industrial group paid a 42% premium for an industrial software company in the same month the market was punishing AI infrastructure names. If AI is going to change how factories run, somebody still has to build the software layer that makes it work.

This article is for informational purposes only and is not investment advice or a solicitation to buy or sell securities. The content is based on publicly available information and reflects the author’s opinions as of the publication date, which may change without notice. All investments carry inherent risks, including the potential loss of principal, and past performance is not indicative of future results. Readers should conduct their own research or consult a financial advisor before making investment decisions. BBAE holds no position in the securities mentioned, nor are they compensated by the companies mentioned.