SK hynix rose 5.18% to 1.34 million won and Samsung Electronics 4.23% to 222,000 won in Seoul on Tuesday, 27 October, Yonhap News Agency reported, as the KOSPI closed up 3.09% at 5,638.34. Yonhap said investor sentiment improved after Anthropic disclosed strong revenuegrowth in its US IPO filing, and that falling oil prices also lifted risk appetite.
On the same morning in Mumbai, Infosys fell 2.31% and Tata Consultancy Services (TCS) 2.09% in intraday trade, Business Today reported at 11:08 IST, with all 10 stocks in the NSE IT index lower.
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Today’s stories in about a minute (27 Oct 2026).
The key insight: As we read it, the moves the outlets tied to the filing ran in opposite directions on Tuesday: chip and memory names closed higher in Seoul and Tokyo, while Indian IT services stocks, which Business Today says had gained on hopes of a global shift away from AI stocks, traded lower.
The Korea Exchange activated a buy-side sidecar at 10:13 a.m., suspending buy orders in program trading for KOSPI-listed shares for five minutes, Yonhap reported. It was the first such action in four trading sessions. The measure is triggered when KOSPI 200 futures rise at least 5% and stay there for one minute or longer.
Foreigners and institutions bought a net 592.97 billion won and 280.38 billion won of shares, while individuals sold a net 947.78 billion won, according to Yonhap. SK Square, the parent of SK hynix, jumped 7.67%, and Samsung Electro-Mechanics 7.42%.
“Foreigners and institutions snapped up major semiconductor stocks amid renewed investment sentiment over AI, despite lingering macroeconomic concerns,” Lee Kyoung-min, an analyst at Daishin Securities, told Yonhap.
Share moves on 27 October 2026: Seoul and Tokyo closes as reported by Yonhap and Reuters; Mumbai moves intraday at 11:08 IST as reported by Business Today.Seoul on 27 October 2026, as reported by Yonhap: the KOSPI closed up 3.09%, SK hynix up 5.18%, and the Korea Exchange paused program buy orders for five minutes at 10:13 a.m.
Update, 27 Oct: SK Telecom, an early Anthropic investor. Chosunbiz reported, citing Korea Exchange data, that SK Telecom was trading at 75,700 won at 9:23 a.m. in Seoul, up 3,600 won or 4.99% from the previous session. Chosunbiz linked the move to attention on the value of SK Telecom’s Anthropic stake after the S-1 filing, and described SK Telecom as one of Anthropic’s early investors.
In its own annual report on Form 20-F, filed with the SEC in April, SK Telecom says: “In August 2023, we made an equity investment of US$100 million in Anthropic PBC, … in order to jointly develop a multilanguage large-language model customized for telecommunications companies.”
SK Telecom does not appear in the S-1’s principal and selling stockholders table, and a search of the filing’s text found no mention of it, so the size of its stake is not stated in the S-1.
What Moved in Tokyo
The Nikkei 225 rose 1.73% to close at 63,268.37, paring an earlier gain of more than 2%, and the broader Topix rose 0.61%, Reuters reported. Chip-testing equipment maker Advantest surged 8.98%, giving the Nikkei its biggest boost; SoftBank Group rose 4.95% and Tokyo Electron 3.07%.
Reuters wrote that the tech-heavy Nikkei tends to move in tandem with the US Philadelphia chips index, which rose 2.8% overnight. “The market was relieved by the news about Anthropic’s IPO, while heavyweight technology stocks tracked a rise in the US chip index,” Daisuke Hashizume, senior strategist at Daiwa Securities, told Reuters.
What Moved in Mumbai
Indian IT stocks had recently gained on hopes of a global shift away from AI stocks, Business Today reported. They fell amid Anthropic’s planned IPO and Meta’s announcement that it was seeking $95 billion through equity offerings, “raising fears that hopes of a ‘reverse AI’ trade may be premature.”
It added that Infosys was particularly down as at least four brokerages cut their ratings on the stock in a single day. We covered the Indian side, and what Infosys and TCS report about their own AI revenue, in our piece on Indian IT this morning.
What the Filing Disclosed
Anthropic’s S-1 puts its future obligations on leases primarily related to compute and infrastructure capacity that had not yet commenced at about $321.4 billion at 30 June 2026, and its fixed or minimum guaranteed purchase commitments at about $265.6 billion, as we reported in our piece on Anthropic’s unstarted compute leases.
Connecting the Coverage
Seoul’s gains came a day after Reuters reported that China’s STAR50 index of AI and semiconductor leaders had fallen 40% in less than four months, wiping out some $480 billion of market value, which we covered as China’s AI index losing $480B.
On memory, Nvidia’s own Vera Rubin NVL72 page now lists 19.2 TB/s of HBM4 bandwidth per GPU, down from 22 TB/s in an August archive of the page, as we reported in our piece on Vera Rubin memory bandwidth.
The Structural Read
As we read it, the Seoul move was large enough to trip an exchange rule: the Korea Exchange’s buy-side sidecar is triggered when KOSPI 200 futures rise at least 5% for a minute, and Yonhap reports it fired at 10:13 a.m.
As we read it, the buyers in Seoul were foreigners and institutions, who bought a net 592.97 billion won and 280.38 billion won, while individuals sold a net 947.78 billion won, according to Yonhap.
As we read it, the biggest single gainer named in Tokyo was a chip-testing equipment maker, Advantest, up 8.98%, ahead of SoftBank Group at 4.95%, per Reuters.
Lee Kyoung-min, Daishin Securities, to Yonhap, 27 October 2026
“Foreigners and institutions snapped up major semiconductor stocks amid renewed investment sentiment over AI, despite lingering macroeconomic concerns.”
Three Implications
FOR CHIP AND MEMORY INVESTORS Yonhap and Reuters both reported that AI-related chip stocks led Tuesday’s gains in Seoul and Tokyo after Anthropic’s filing.
FOR THE ‘REVERSE AI’ TRADE Business Today reported that Indian IT stocks had gained on hopes of a shift away from AI stocks, and that Tuesday’s fall raised fears those hopes may be premature.
FOR READING THE MOVES Yonhap also named falling oil prices and Reuters the US chip index, and the Indian figures are intraday, so the share of each move due to the filing is not known.
The framework puts it in one line: “Memory is becoming the new compute.”
As we read it, the two memory makers, SK hynix and Samsung Electronics, rose 5.18% and 4.23% in Seoul on Tuesday, per Yonhap. The framework was published in December 2025 and does not discuss Anthropic’s filing or these moves.
What Is Not Established
Yonhap named falling oil prices as well as Anthropic’s filing, and Reuters tied the Nikkei to the US chip index, so the share of each move due to the filing is not known. Business Today also linked the Indian fall to Meta’s equity offering and Infosys to brokerage downgrades.
The Seoul and Tokyo figures are closing moves; the Indian figures are intraday from Tuesday morning and may differ at the close.
This Week In The AI Supercycle
Execution Fault Lines, Concentrated Demand, and Geopolitical Firewalls
This week’s issue: the AI build is not short of demand for its parts. It is short of cheap money, and its end revenue rests on a narrow base of large, often venture-funded buyers.
On Tuesday, the day after Anthropic’s filing, SK hynix closed up 5.18% and Advantest 8.98%, and Seoul paused program buying for five minutes, while Infosys and TCS traded down more than 2% in Mumbai. Business Today wrote that the Indian fall raised “fears that hopes of a ‘reverse AI’ trade may be premature.”
A note on sourcing. This piece is based on Yonhap’s Seoul closing report and Reuters’ Tokyo closing report of 27 October 2026 (as syndicated by Livemint) and the Business Today report of 27 October 2026 (11:08 IST), read in full on 27 October 2026, and on our own earlier reporting. Stock moves are as reported by those outlets; the Indian moves are intraday. We did not contact the companies named or Anthropic.
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.
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