Korea's Top 10 Conglomerates Lose $830 Billion in a Month as Kospi Plunges and Samsung, SK Chip Rout Deepens

SEOUL, South Korea — South Korea's 10 largest business groups have lost more than 1,100 trillion won (about $830 billion) in combined stock market value in less than a month. A sharp selloff in technology shares has pulled down the country's benchmark index.

The combined market capitalization of the 10 groups' listed companies stood at about 3,371 trillion won ($2.55 trillion) as of Friday. That compares with about 4,473 trillion won ($3.38 trillion) at the end of September, according to data from the Korea Exchange and financial information provider FnGuide, as reported by South Korean media on Sunday.

The decline of roughly 1,101 trillion won means the country's leading conglomerates lost nearly a quarter of their value in under four weeks.

Over the same period, the benchmark Kospi index fell from 6,838.04 to 5,550.30. That was a drop of 1,287.74 points, or 18.83%. The conglomerates' market value fell about 24.6%, a decline 5.79 percentage points steeper than the index.

Chipmakers take the hardest hit

The losses were concentrated in the two groups that own the country's semiconductor giants, Samsung Electronics and SK Hynix.

SK Group posted the steepest percentage decline among the 10 groups. Its market value fell 30.1%, from about 1,563 trillion won at the end of September to about 1,093 trillion won. SK Square, the group's investment arm and SK Hynix's largest shareholder, fell 31.96%, from 1,139,000 won to 775,000 won per share.

Samsung Group recorded the biggest loss in absolute terms. Its market value fell 24.30%, from about 2,161 trillion won to about 1,636 trillion won. That was a drop of roughly 525 trillion won ($397 billion), the largest among the 10 groups.

Samsung Electronics shares fell 20.04% over the period, from 269,500 won to 215,500 won.

Together, Samsung and SK lost about 995.6 trillion won ($753 billion) in market value, or 90.4% of the total decline across the 10 groups.

Shipbuilding and others also slide

HD Hyundai Group, the shipbuilding and heavy industry conglomerate, had the second-largest percentage decline. Its market value fell 25.6%, from about 128 trillion won to 95 trillion won.

Other groups also lost value, though less sharply:

• Hanwha: down 19.35%
• Hyundai Motor: down 14.98%
• GS: down 12.97%
• Shinsegae: down 11.94%
• POSCO: down 6.43%
• LG: down 5.30%
• Lotte: down 4.30%

Global AI selloff

The slump in South Korean shares is part of a global retreat from stocks tied to artificial intelligence. Investors are questioning how long tech companies can keep spending heavily on AI data centers and how that spending will be funded.

South Korean chip stocks had soared earlier this year on surging demand for memory chips used in AI systems, particularly high-bandwidth memory. Those gains made the market especially vulnerable when sentiment turned.

On Oct. 13, Samsung shares fell 7.4% and SK Hynix tumbled about 10% in a single session. The selling briefly pushed the Kospi below 6,000. Foreign investors sold about 2.36 trillion won of SK Hynix shares and about 1.36 trillion won of Samsung shares that day alone.

Several worries have converged. Reports that China's CXMT is advancing new memory chip technology raised fears of tougher competition. U.S. Treasury yields above 5% have increased pressure on richly valued growth stocks. Oil prices above $100 a barrel, driven by the conflict involving Iran, have added to inflation concerns.

On Friday, Reuters reported that the selloff in AI-related shares "drove investors into safer assets globally," as South Korean stocks headed for a second straight weekly loss.

Profits still at records

The stock market losses contrast sharply with the chipmakers' earnings. Samsung said in preliminary results on Oct. 8 that it expects record third-quarter operating profit of 107.4 trillion won, about $80 billion. Analysts surveyed by FnGuide expect SK Hynix to report record quarterly operating profit of about 77 trillion won.

Both companies report full quarterly results this week, SK Hynix on Wednesday and Samsung on Thursday. Investors are watching for signs that demand for AI memory chips remains strong, and for new measures to return money to shareholders.

SK Hynix said it will announce additional shareholder return measures alongside its results. Its shares rose 4.4% on Thursday after the company halted a review of a possible stock listing for its U.S. storage subsidiary, Solidigm.

"We expect more effective and concrete measures to boost shareholder value to be presented at the upcoming earnings call," Kim Sun-woo, an analyst at Meritz Securities, said.

Retail investors exposed

The decline has hit South Korea's large base of individual investors, who poured money into chip stocks during this year's rally. Retail investors bought a net 31.5 trillion won of SK Hynix shares from April to June alone.

About 74% of SK Hynix shareholders were sitting on losses as of Oct. 19, according to NH Investment & Securities.

Both chipmakers recently completed large share buyback programs, which had helped support their stock prices. SK Hynix finished about 40 trillion won in purchases on Oct. 21, and Samsung's buyback of about 15 trillion won ended Oct. 6. Analysts say the end of those programs could add to near-term volatility.

Concentration risk

The scale of the losses highlights how heavily South Korea's stock market depends on a handful of companies. Samsung and SK Hynix make up a large share of the Kospi's total value, so swings in chip stocks can move the entire index.

Even after the recent decline, the Kospi remains up for the year, helped by gains earlier in 2026 driven by the AI boom and government efforts to boost corporate value and shareholder returns.

Whether the index can recover may depend on this week's earnings reports and on whether global investors regain confidence in the long-term outlook for AI spending.