The quick read: • Korea's KOSPI closed down 3.65% on Monday, Oct 12, at 6,384.24, its first close below 6,400 since Aug 11, per Bloomingbit and SBS. • Foreign investors net sold about 2 trillion won (about $1.5 billion) that day. Samsung Electronics fell 4.39% and SK Hynix 4.52%, per Bloomingbit. • A Mirae Asset Securities analyst said the two chipmakers were "absorbing renewed AI-bubble concerns stemming from the OpenAI revenue debate," per Invezz. • The debate: on Oct 8 the Financial Times reported OpenAI told investors its annualized revenue is approaching $50 billion. Earlier reports had put it near $68 to $70 billion, per TechCrunch and Yahoo Finance. • Seoul was closed Friday, Oct 9, for Hangeul Day, so Monday was its first session after the news. U.S. chip stocks, slowing earnings and Middle East tensions also weighed. • OpenAI's response: the company attributed the gap to differences in accounting methods, per SBS. Reporting says OpenAI does not count sales made by cloud partners the way Anthropic does. • For a small business: the AI vendor behind your tools is now a market risk, and its numbers are hard to read from outside.
“OpenAI's $20 Billion Revenue Gap Hit Korea's Stock Market”
who’s making the noise
Korea market close of Mon Oct 12, 2026 (SBS, Bloomingbit, Invezz). OpenAI revenue figures from the Financial Times, Oct 8, as reported by TechCrunch (Oct 8) and Yahoo Finance (Oct 9).
our take
OpenAI is a private company. It is not listed on any stock exchange. On Monday its revenue figure still helped move a whole country's market. Korea had been closed on Friday, so it absorbed the week's AI selloff in one session, and the selling ran through the two companies that make the memory chips AI runs on. OpenAI's side, stated fairly: the company says the gap comes from accounting, not from lost sales. Its disclosures to investors show strong growth, and several analysts called last week's selloff overblown. We take that as reported. It is also a reminder that the most-watched number in AI depends on how the company chooses to count it. The individual investors were the only net buyers in Seoul on Monday, at about 1.47 trillion won (about $1.1 billion). Foreign funds sold, institutions sold, ordinary people bought. The plain move for a small business: write down which AI company each of your tools runs on, and check that you can export your data and prompts. If one vendor's numbers can shake a stock market, a plan B for your own workflows is cheap insurance. What to watch: whether OpenAI publishes a revenue figure on its own terms, TSMC's earnings this week, and whether Korea's chip stocks recover.