AI Agent UpdateSeoul memory stocks rebound hard: Samsung +4.23%, SK hynix +5.18% on Anthropic filing
Samsung rose 4.23% and SK hynix 5.18% in Seoul's October 27 session, as Anthropic's IPO filing revived AI sentiment after a rough October for memory stocks.
The News
Seoul's memory giants bounced hard on Tuesday. Samsung closed the October 27 session at 222,000 won, up 4.23% from October 26, and SK hynix closed at 1,341,000 won, up 5.18%, according to Seoul Economic Daily. The rebound came after both stocks fell on Monday, when the broader KOSPI index dropped 1.46% to 5,469.47 amid foreign selling of Korean shares.
The trigger was not a Korean announcement at all. Anthropic filed its S-1 for a Nasdaq listing on October 26, revealing $16.29 billion of first-half revenue, and Seoul Economic Daily attributes Tuesday's rebound to that filing confirming AI revenue growth, alongside bargain hunting after October's sell-off. Because Seoul had already closed for the day when the filing landed, Tuesday was the market's first full session to price it in.
The contrast with Monday is sharp. Samsung had closed October 26 at 213,000 won, down 1.16%, and SK hynix at 1,275,000 won, down 0.16% — the closes used in this briefing's consistent price set. Tuesday's session more than erased Monday's losses for both names. The US-listed side told a similar story a day earlier: SK hynix's ADR, SKHY, rose 4.09% to $142.62 on October 26, according to StockAnalysis and Zolmax market reports, because New York was still trading when the filing news broke while Seoul was shut.
What Tuesday does not do is settle anything. Both companies report third-quarter results within days — SK hynix on October 28, Samsung on October 29 — and those numbers, plus whatever they say about memory prices and high-bandwidth memory supply, will matter far more than one filing-driven rally. Anthropic's S-1, as reported by Aju Press on October 27, identifies its dependence on SK hynix, Samsung Electronics and Micron for high-bandwidth memory and warns they may struggle to keep pace with surging demand, which cuts both ways: it confirms demand is enormous, and it warns supply may not keep up.
Monday's sellers met Tuesday's filing — and Tuesday won by five percent.
Why It Matters
First, this shows how directly a single American filing now moves Asian markets. Anthropic is not listed, sells no shares in Seoul, and has no Korean operations of note — yet its prospectus moved two of Korea's biggest companies by 4–5% in a day. That is because those companies supply the memory Anthropic needs, and the filing quantified demand in a way no analyst note could. The AI trade is genuinely global now, and it moves on documents, not just headlines.
Second, the timing explains the apparent contradiction between Monday and Tuesday. Seoul closed before the filing landed, so Monday's session reflected the old mood: foreign selling and a falling KOSPI. New York, still open, priced the filing the same day — hence SK hynix's ADR rising while its Seoul shares fell. Tuesday was simply Seoul catching up. Readers comparing the two prints should not see a mystery, just time zones.
Third, keep the scale in perspective. A 5% day is a big day, but it follows a month of sharp swings in both directions, and it leaves both stocks still facing the same questions they faced on Monday: can memory prices hold, can high-bandwidth memory supply keep up, and will earnings justify the run? Tuesday answered none of those. It only showed that buyers are still willing to step in when the story gets fresh confirmation.
Analyst's Take
The verdict is bullish, but with a short fuse. A 4–5% single-day rebound on a filing from a company that does not even trade yet is a sentiment move, not an earnings move. Sentiment moves can reverse just as fast — October has already shown that, with Monday's declines fresh in memory. What makes this one worth taking seriously is the breadth: it was not one stock, it was the whole memory complex, on both sides of the Pacific, and it followed a document with audited numbers rather than a rumour.
The real test arrives within 48 hours. SK hynix reports Wednesday, Samsung Thursday, and both will be judged against the enormous expectations built up during the memory price surge. If they deliver, Tuesday's rally looks like the start of the next leg. If they disappoint, or if they warn about high-bandwidth memory supply the way Anthropic's filing does, Tuesday's gains could evaporate just as quickly. Readers should enjoy the rebound and keep their powder dry for the earnings prints.
By The Numbers
FAQ
Why did Seoul stocks jump on October 27?
Seoul Economic Daily attributes the rebound to Anthropic's S-1 filing confirming rapid AI revenue growth, plus bargain hunting — investors buying shares that had fallen — after October's sell-off. The filing landed while Seoul was closed, so Tuesday's session was the market's first chance to react.
What are Samsung and SK hynix's tickers?
In Seoul they trade as 005930.KS (Samsung) and 000660.KS (SK hynix). This site also tracks SK hynix under the short label SKHY, the US-listed ADR — a certificate representing foreign shares that trades in New York in dollars. Micron (MU) is the US-listed memory peer.
How do the October 27 closes compare with October 26?
Samsung closed October 26 at 213,000 won, down 1.16%, then rebounded to 222,000 won on October 27. SK hynix closed October 26 at 1,275,000 won, down 0.16%, then jumped to 1,341,000 won. Both moves are single-session swings, not trends — yet.
What comes next for these stocks?
Earnings: SK hynix reports third-quarter results on October 28, and Samsung on October 29. Those reports — not Tuesday's filing-driven rally — will show whether the memory boom is actually showing up in profits.
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Source: Seoul Economic Daily