Chip Equipment and Optical Stocks Take the Hardest Hit in a Brutal AI Selloff Week
Chip equipment makers fell an average of 15.8% over five sessions, the deepest decline among sector groups on this week's list of losers, followed by optical, crypto-hosting and AI hardware stocks, as AI financing worries, Meta's spending plans and Lam Research's supply warning hit the buildout trade.
A sweeping AI-infrastructure selloff left 87 of the 248 stocks on this week's list of losers down more than 10% over five sessions, and the damage was deepest in the companies that build the machines, light and power behind AI data centers. Chip equipment makers fell an average of 15.8%, the worst of any sector group on the list, followed by optical and networking names (14.9%) and crypto miners and AI-hosting companies (13.9%). In dollar terms the largest hit landed on mega-cap tech, which by our calculation lost about $791B in market value, led by Alphabet and Meta.
How to read this. The data is a screen of the weakest stocks over five sessions as of Oct. 22 (the file supplied), covering companies with market values from about $1 billion up, with Alphabet counted once. We assigned each stock to a sector group, so group averages describe the losers in that group, not the whole sector. Value erased is each stock's market value divided by one plus its five-day change, minus the current value, by our calculation; it ignores share-count changes.
Which sectors were hit hardest
The answer depends on whether you measure depth or dollars. Chip equipment, optical gear, crypto-hosting and AI hardware names fell furthest, while mega-cap tech and chip designers lost the most value because of their size. The 121 stocks in the nine AI-infrastructure groups fell an average of 12.6%, against 5.3% for the other 127 names on the list.
Chip designers erased about $371B even though their average decline was 11.2%, and memory and storage lost about $240B, led by SK hynix, Micron and Sandisk by value. Memory fell less than most AI hardware groups, at 8.6% on average.
The 24 worst names
TTM Technologies topped the list with a 37.6% five-day decline, followed by Forgent Power Solutions (−29.1%), Coherent (−28.7%), VNET (−28.6%) and DigitalOcean (−28.5%). The worst 24 stocks come almost entirely from optical, hardware, power, cloud and crypto-hosting groups, with chip equipment represented by FormFactor, Aehr Test Systems and Applied Materials.
Why it happened
No single event explains the week. Four developments compounded, according to market coverage. The prior week brought a hot inflation print that pushed rate-hike bets higher and a debt scare at AI cloud provider CoreWeave, and this week added Meta's higher spending plans and a supply warning from Lam Research. Stocks bounced from Oct. 19 to Oct. 21, with the Nasdaq up about 1% on Wednesday, before the last two reports reopened the selloff.
Hot inflation
September CPI rose 3.7% from a year earlier against 3.6% expected, according to Vantage Markets. The 10-year Treasury yield briefly touched 5.33% before closing at 5.19%, and markets briefly priced about a 50% chance of a Fed hike this month, falling to about 37% by the close.
AI debt scare
A viral chart showed CoreWeave bonds yielding more than 15%. The neocloud has about $50 billion of obligations. CoreWeave fell more than 15% and Oracle 8.8% on Oct. 14, according to SiliconANGLE. The Nasdaq 100 fell 2.5% on Oct. 16, and the Nasdaq Composite lost 4.48% that week, its worst since late June, per Vantage.
Meta's spending bill
Meta beat on revenue but guided 2026 capex to $135–145 billion, posted negative free cash flow of $2.12 billion and said it will create nonvoting Class C stock, per BusinessToday. CFO Susan Li said there are "no specific financing plans to announce at this time." GE Vernova fell about 11%, Vertiv 7% and Eaton 6% on Thursday, according to 24/7 Wall St.
Lam's supply warning
Lam Research posted record revenue of $8.22 billion, but said clean room space and component shortages capped its outlook and would limit chipmakers into 2027. Lam fell about 9%, Applied Materials 6% and ASML 4% on Thursday, while Marvell and AMD fell 8% and Intel 7%, per 24/7 Wall St.
Lam's management pushed back on the alarm. CEO Tim Archer said the tightness is "nothing like" the COVID-era shortages and that the company will be "caught up very shortly," and the CFO expects delayed shipments to land in the March quarter. Lam also cited visibility through 2028 and a preliminary outlook for more than $200 billion of wafer fab equipment spending in 2027.
Sector scorecard
The table sorts each group by market value erased and lists the developments reported for it.
| Sector group | Stocks | Avg. 5-day | Median | Value erased | Worst name | What was reported |
|---|---|---|---|---|---|---|
| Mega-Cap Tech & Software | 18 | −6.2% | −5.7% | $791B | U −13.3% | Meta's capex outlook and negative free cash flow; Alphabet reports Oct. 28 |
| Chip Designers | 18 | −11.2% | −10.8% | $371B | CBRS −22.4% | Lam's supply warning; Marvell and AMD −8%, Intel −7% on Oct. 22 |
| Chip Equipment | 13 | −15.8% | −17.0% | $246B | FORM −20.0% | Lam Research's supply-constraint warning on Oct. 21; earlier profit-taking after a big year |
| Memory & Storage | 7 | −8.6% | −8.9% | $240B | P −14.1% | Toshiba's plan to double hard-drive capacity; Western Digital reports after Thursday's close |
| Everything Else | 75 | −4.2% | −3.9% | $170B | CLMT −17.3% | Broad weakness across energy, financials, consumer and health care names |
| Power Gear & Build-out | 24 | −12.5% | −12.0% | $140B | FPS −29.1% | Meta's financing questions; GE Vernova −11%, Vertiv −7%, Eaton −6% on Oct. 22 |
| Optical & Networking | 11 | −14.9% | −12.3% | $129B | COHR −28.7% | Moved with the broader AI-hardware selloff |
| AI Servers & Hardware | 13 | −13.4% | −12.5% | $103B | TTMI −37.6% | CoreWeave debt scare (Dell −11.3% on Oct. 14); TTM Technologies' post-earnings plunge |
| Metals & Mining | 19 | −8.1% | −7.3% | $53B | USAR −15.2% | Outside the AI complex; declines averaged about 8% |
| AI Cloud & Data Centers | 12 | −11.6% | −7.6% | $35B | VNET −28.6% | CoreWeave's roughly $50B of obligations; Oracle −8.8% on Oct. 14 |
| Space, Defense & Airlines | 15 | −6.7% | −6.3% | $32B | ASTS −18.6% | Outside the AI complex; AST SpaceMobile led the group lower |
| Power Producers & Nuclear | 9 | −9.0% | −8.7% | $32B | CEG −13.9% | Fell in step with AI-power peers |
| Crypto Miners & Hosting | 14 | −13.9% | −14.4% | $13B | CIFR −27.8% | CoreWeave debt scare; TeraWulf and Hut 8 fell more than 10% on Oct. 14 |
Sources: The weekly-losers screen supplied (five-day changes as of Oct. 22); Vantage Markets (Oct. 19); SiliconANGLE (Oct. 14); BusinessToday (Oct. 22); 24/7 Wall St. (Oct. 13 and Oct. 22); Yahoo Finance (Oct. 21). Sector groupings, averages and market value erased are our calculations from that screen. Reported moves are intraday as given by those outlets and may differ from closes. This is informational, not a recommendation to buy or sell.
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