SK hynix and Samsung Electronics lost about $85.0 billion of stock market value between them on 3 November, by our arithmetic, at Korea Exchange closing prices (06:30 UTC) and the share counts in their own filings. In New York, Micron was up 2.02% at $850.43 at 18:23 UTC, per Yahoo Finance quote data, about $19.05 billion of added value on the 1,131,423,212 shares on its 10-K cover.
It was the first session for both markets since Apple reported its fiscal fourth quarter after the US close on 2 November. At 18:23 UTC Apple was down 1.79% at $332.27, about $87.9 billion of market value on the 14,532,182,000 shares in its fiscal 2026 10-K, by our arithmetic. We set the moves side by side; none of the sources ties one to another.
Business Pill ยท The Memory Wall
An evergreen Business Engineer explainer on memory as a constraint. It teaches the general idea only and does not discuss any company’s share price.
The key insight: By our arithmetic, SK hynix and Samsung lost about $85.0 billion of market value at the Korea Exchange close on 3 November and Micron added about $19.05 billion by 18:23 UTC, while Apple, whose 10-K says it expects memory and storage cost trends to intensify, was down about $87.9 billion.
SK hynix closed at 1,398,000 won, down 5.03% from 1,472,000, according to Korea Exchange closing data on Google Finance. On the 730,492,365 issued shares in its 26 October filing, that is 54.06 trillion won, or about $40.3 billion at 1,340.58 won per dollar, by our arithmetic.
Samsung Electronics common shares closed at 219,500 won, down 4.15%, and its preferred shares at 171,600 won, down 3.05%. On the 5,846,278,608 common and 802,371,203 preferred shares in its half-year report, the two classes lost about $44.7 billion, or about 4.0% of their combined value, by our arithmetic.
In the US, Sandisk was up 3.47% at $1,112.34 at 18:23 UTC, about $5.3 billion on its 10-Q share count, so Micron and Sandisk together added about $24.4 billion by our arithmetic. Western Digital, a storage maker, was up 1.33%, about $1.7 billion.
Change in stock market value on 3 November 2026 from the 2 November close: SK hynix and Samsung at the Korea Exchange close (06:30 UTC), Micron, Sandisk and Apple at 18:23 UTC. Our arithmetic: price times the shares in each company’s filings; won at 1,340.58 per dollar. Chart: FourWeekMBA.
What Apple Said About Memory
Apple’s 10-K, which we covered in Apple’s 10-K Shows $117B in Purchase Commitments, says: “For example, the Company is experiencing supply constraints and rising costs driven by industry-wide supply-demand imbalances for key components, including advanced semiconductors, memory and storage”. It adds: “The Company expects these trends to intensify for memory and storage components”.
Micron’s 30 September earnings release reported fiscal fourth-quarter revenue of $54.23 billion, against $11.32 billion a year earlier, at a GAAP gross margin of 86.8%. For its fiscal first quarter of 2027 it guided revenue of $61.5 billion, plus or minus $1.5 billion, and a GAAP gross margin of approximately 85.95%.
By our arithmetic, Micron’s guided gross margin is about 40 points above the 45.5% midpoint of Apple’s December-quarter guide. Chief executive Sanjay Mehrotra said in the release: “Micron delivered record fiscal 2026 results, and we expect an even stronger fiscal 2027”.
Why Korea Fell
Korea’s session ran from 00:00 to 06:30 UTC, after Apple’s report and before the US open at 14:30 UTC. As we reported in Samsung, SK Hynix Drop 3% on AI Doubts, Yonhap said South Korean stocks plunged, “driven by heavy tech sell-offs amid escalating woes about massive artificial intelligence (AI) spending”. The KOSPI ended at 5,648.79, down 3.59%.
Memory prices themselves were still rising in October: the 8-gigabit DDR4 DRAM average hit a record $27.50, per DRAMeXchange data reported by TheElec, which we covered in DRAM Prices Hit a Record.
The Structural Read
As we read the day, the memory makers did not move as one group: the two Korean makers fell in the first Korean session after Apple’s results, while the two US memory makers rose in New York, and no source we read gives a reason for the US rise.
As we read the filings, the two sides of the trade are on the record: Apple’s 10-K expects memory and storage cost trends to intensify, and Micron guided a GAAP gross margin of approximately 85.95% for its fiscal first quarter of 2027, about 40 points above the midpoint of Apple’s December-quarter guide by our arithmetic.
Apple Form 10-K, fiscal 2026
“The Company expects these trends to intensify for memory and storage components”
Three Implications
FOR KOREA’S MEMORY MAKERS By our arithmetic, SK hynix lost about $40.3 billion and Samsung’s two share classes about $44.7 billion at the Korea Exchange close; Yonhap tied the market’s fall to worries about AI spending.
FOR MICRON By our arithmetic, Micron’s 2.02% rise to $850.43 at 18:23 UTC is about $19.05 billion on its 10-K share count; the figure moves with each trade.
FOR APPLE’S SHAREHOLDERS By our arithmetic, Apple was down about $87.9 billion at 18:23 UTC, after about $166 billion at 14:36 UTC and $114.4 billion at 16:14 UTC.
The framework includes, in bold, the sentence “Memory is becoming the new compute.”
As we read it, 3 November showed both sides of that constraint in one day: a device maker whose filing expects memory costs to keep rising, and memory makers whose share prices moved in opposite directions in Seoul and New York. The framework does not discuss these companies’ share prices.
No source we read links the Korean or US memory moves to Apple’s results, and none gives a reason for Micron’s or Sandisk’s rise. The moves are parallel, not cause and effect.
The US figures are intraday at 18:23 UTC and move with each trade. The Korean counts are issued shares, including treasury shares: SK hynix’s filing says 23,693,272 of its shares are to be cancelled on 5 November, and Samsung’s June count includes 82,086,705 common shares in treasury. On outstanding shares, the Korean losses would be slightly smaller. After-hours trading on the Nextrade venue ended at 1,414,000 won for SK hynix and 222,000 won for Samsung, per Naver Finance; our figures use the Korea Exchange close.
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By our arithmetic, SK hynix and Samsung lost about $85.0 billion at the Korea Exchange close on 3 November, Micron added about $19.05 billion by 18:23 UTC, and Apple was down about $87.9 billion, on the day after Apple guided its margin lower and its 10-K said it expects memory and storage cost trends to intensify.
A note on sourcing. Korean prices are Korea Exchange closing prices for 3 November 2026 (15:30 Seoul time, 06:30 UTC); US prices are Yahoo Finance regular-session quote data read at 18:23 UTC. Share counts are from the companies’ latest filings with the SEC and with Korea’s DART system; won are converted at 1,340.58 per dollar. Market values and changes are our arithmetic (price times shares). We did not contact the companies.
Gennaro Cuofano is a CRO and tech executive who has worked in AI since late 2015, starting with bringing NLP, natural-language generation, voice and chatbot products to the marketing industry. His background is in law and finance: he holds a Master's degree in Law and an International MBA with an emphasis on corporate finance (LUISS Business School and the University of San Diego, 2012), and worked as a financial analyst at a real-estate investment firm in San Diego and as an assistant controller. His work focuses on business model strategy, business engineering and, more broadly, structural analysis: how companies make money, read from their own filings. He created FourWeekMBA and leads research there and at The Business Engineer, his newsletter on AI and business strategy, with over 95,000 subscribers and more than 1,000 published analyses. His writing has also appeared on Entrepreneur (for example, How to Digitize a Family Business in Europe) and HackerNoon. Find him on LinkedIn and Substack. See how we source.
