Samsung Electronics traded at 221,750 won and SK hynix at 1,422,000 won at 10:17 Seoul time on 3 November, down 3.17% and 3.40%, according to Korea Exchange data on Naver Finance. The KOSPI was at 5,715.39, down 2.45%, after touching 5,638.06, 3.77% below Monday’s close by our arithmetic. These are intraday levels; the session closes at 15:30.
By our arithmetic, that intraday KOSPI level is 37.3% below the index’s record close of 9,114.55 on 22 June 2026, and still 35.6% above the 4,214.17 at which it ended 2025.
Business Pill · The Memory Wall
An evergreen Business Engineer explainer on memory as a constraint. It teaches the general idea only and does not discuss this session.
The key insight: Samsung Electronics and SK hynix were down 3.17% and 3.40% at 10:17 Seoul time on 3 November, and the KOSPI’s intraday level of 5,715.39 is 37.3% below its 22 June record close of 9,114.55, by our arithmetic, as Seoul Economic Daily reported resurfaced doubts over AI profitability.
Update, 3 Nov, 03:00 GMT: Taiwan joins the selloff, TAIEX down 822 points intraday. The selloff spread to Taipei. At 11:00 Taipei time (03:00 GMT) the TAIEX stood at 44,098.01, its low of the session so far, against Mondayโs close of 44,920.14, according to Taiwan Stock Exchange market data. By our arithmetic that is down 822.13 points, or 1.83%. TSMC (2330.TW) traded at NT$2,315 at the same time, down 0.64% from NT$2,330, according to Yahoo Finance Taiwan, after touching NT$2,295. Its New York-listed shares (NYSE: TSM) closed on Monday, 2 November, at $398.63, down $7.50 or 1.85%, according to Nasdaq.com. The Taipei Times, citing CNA, reported on Tuesday that โconcerns over massive spending on artificial intelligence (AI)โ had โtriggered a global sell-off of technology stocksโ. It quoted National Development Council Minister Yeh Chun-hsien as saying the impact on Taiwan should be short-term, because local hardware makers โcontinue to receive substantial ordersโ. Seoul was weaker still. At 12:00 Seoul time the KOSPI was at 5,660.35, down 3.39%, with Samsung Electronics at 220,000 won (down 3.93%) and SK hynix at 1,399,000 won (down 4.96%), according to Korea Exchange data on Naver Finance. Our read: at 11:00 TSMCโs 0.64% drop was about a third of the indexโs 1.83%, so the selling in Taipei was broader than its largest company. All figures are intraday. Taiwan closes at 13:30 local time (05:30 GMT) and Korea at 15:30 (06:30 GMT).
Seoul Economic Daily reported before the open that the two chipmakers “both fell more than 3% in pre-market trading as concerns resurfaced over the profitability of artificial intelligence investments”. In the Nextrade pre-market, it said, Samsung traded at 222,000 won, down 3.06%, and SK hynix at 1,419,000 won, down 3.60%.
The paper tied the mood to Wall Street. It reported that the Nasdaq fell 1.1% and the S&P 500 0.5% overnight, while “Oracle plunged 8.8%, while Micron and Nvidia dropped 5.8% and 1.3%”. It wrote that “Oracle’s plan to raise $20 billion through stock and bond sales rekindled debate over the capital spending burden and profitability of AI companies”.
It also pointed to an offset: West Texas Intermediate crude fell more than 7% to $96.2 a barrel on hopes for US-Iran talks, and the 10-year US Treasury yield fell to 4.91%. Analysts it cited said it “remains to be seen whether they translate into lower actual funding costs” for AI companies.
KOSPI daily closes from 30 December 2025 to 2 November 2026 and the 3 November intraday level at 10:17 Seoul time, from Korea Exchange data on Naver Finance. The intraday level is 37.3% below the 22 June record close of 9,114.55 and 35.6% above the end-2025 close of 4,214.17, by our arithmetic; it is not a closing level.Animated: KOSPI at each week’s last close from 2 January to 30 October 2026, then the 3 November intraday level at 10:17 Seoul time, from Korea Exchange data on Naver Finance. The 37% and 36% are our arithmetic. Chart: FourWeekMBA.
Who Was Selling
Naver Finance’s investor tally for the KOSPI, as of about 10:17, showed foreign investors as net sellers of about 556.7 billion won and institutions of about 378.7 billion won, with individuals net buyers of about 870.8 billion won. Falling stocks outnumbered rising ones, 678 to 189.
Both chipmakers sit well below their 52-week highs. By our arithmetic, Samsung’s 221,750 won is 41.6% under its 380,000-won high, and SK hynix’s 1,422,000 won is 52.6% under its 3,002,000-won high. At 10:15 the two carried market values of about 1,292 trillion won and 1,037 trillion won on Naver’s figures.
How the Index Got Here
The KOSPI closed at 6,838.04 on 30 September and at 5,730.74 on 30 October, a 16.2% fall in October by our arithmetic. Inside that month it lost 7.57% on 15 October and gained 6.63% on 28 October, when it closed above 6,000. It rose 2.24% to 5,859.08 on Monday before today’s fall.
Seoul Economic Daily quoted Han Ji-young, an analyst at Kiwoom Securities: “Price corrections in AI stocks have already run a considerable course since October, and macro conditions are deteriorating less than before”. The paper notes its English text is AI-translated from Korean.
As we read it, the business lever is the cost of financing the build-out: the same session that priced in Oracle’s fundraising plan marked down the two suppliers of the memory that build-out uses. That is a reading of one session, not a forecast.
As we read it, the two chipmakers are being priced on their customers’ ability to pay for the build-out: the trigger Seoul Economic Daily names is Oracle’s plan to raise $20 billion, not a change at Samsung or SK hynix.
As we read it, the fall sits on top of a long one: by our arithmetic the index lost 16.2% in October, and SK hynix’s 1,422,000 won is 52.6% under its 52-week high of 3,002,000 won.
As we read it, the selling and buying split by investor type: Naver Finance’s running tally showed foreign investors and institutions as net sellers and individuals as net buyers in the first hour and a quarter.
Han Ji-young, Kiwoom Securities, quoted by Seoul Economic Daily
“Price corrections in AI stocks have already run a considerable course since October, and macro conditions are deteriorating less than before”
Three Implications
FOR MEMORY SUPPLIERS SK hynix said on its third-quarter call that the volumes customers are requesting exceed more than twice what it can supply, according to our earlier coverage; the share price fell 3.40% intraday on 3 November all the same.
FOR KOREA’S INDEX Chips made up 49% of Korea’s exports in October, as we reported, and the KOSPI fell 16.2% in October by our arithmetic.
FOR AI BORROWERS Seoul Economic Daily wrote that Oracle’s plan to raise $20 billion through stock and bond sales rekindled debate over the capital spending burden and profitability of AI companies.
The framework puts it this way: “The thesis: the capex race is no longer a corporate spending cycle.”
As we read it, the Seoul session fits that frame: the trigger Seoul Economic Daily names is a financing event, Oracle’s $20 billion plan, and the shares that fell were those of the memory makers that supply the build-out. The framework does not discuss this session.
The prices here are intraday readings taken before the 15:30 close; closing levels and full-day foreign selling were not available when we wrote this. The link between today’s fall and AI-profitability doubts is Seoul Economic Daily’s account, not a statement from either company; we did not find a comment from Samsung or SK hynix on the session in the sources we read. Investor figures are Naver Finance’s running tally, in 100-million-won units, converted by us.
This Week In The AI Supercycle
Anthropic’s Reality Check, The Capital Squeeze, & The New World Order
This week’s issue: for two years the AI build-out was priced as a growthstory. This week it started being priced as a credit story.
Samsung and SK hynix fell more than 3% in early Seoul trading as, Seoul Economic Daily reported, doubts over AI profitability resurfaced. At 5,715.39 intraday, the KOSPI is 37.3% below its June record close and 35.6% above its end-2025 level, by our arithmetic.
A note on sourcing. Prices and investor figures are intraday readings of Korea Exchange data on Naver Finance at about 10:15 to 10:17 Seoul time on 3 November 2026 and will differ from the close. The stated cause is Seoul Economic Daily’s report. Figures labelled our arithmetic are our own calculations.
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.
