Reference time: Korea time 19:50

On a Black Tuesday, profit-taking in the crowded semiconductor trade erupted all at once, sending KOSPI down 9.99% in a single day and triggering this year’s fourth circuit breaker.

KOSPI closed at 8,203.84. It fell 910.71 points (-9.99%) from the previous session, the largest point decline in the index’s history. The open was 9,083.54, the high was 9,175.45, and the low was 8,203.84, meaning the closing level was also the day’s low. Trading volume was about 483.71 million shares.

KOSDAQ closed at 891.52. It fell 76.88 points (-7.94%), breaking below the 900 line. The open was 958.64, the high was 971.69, the low was 891.52, and trading volume was about 782.72 million shares.

At 오전 11시37분 on KOSDAQ and 오전 11시40분 on KOSPI, temporary suspensions of program sell quotes, or sell-side sidecars, were triggered in succession. Around 오후 2시33분, KOSPI fell into the 8% range, triggering a Level 1 circuit breaker. It was the fourth time this year.

On KOSPI, foreign investors net sold about 4.16 trillion won, and institutions net sold about 4.549 trillion won. Together, the two groups unloaded 8.7 trillion won worth of shares. On the other side, individuals net bought about 8.59 trillion won. It was the largest daily net purchase by individuals on record.

Selling was concentrated in the electrical and electronics sector. In that sector alone, foreign investors sold about 3.2555 trillion won, institutions sold about 4.0541 trillion won, and individuals absorbed about 7.2449 trillion won. By source, there were small differences in the tallies, with foreign net selling reported at 4.1576 trillion to 4.1691 trillion won and individual net buying at 8.5795 trillion to 8.5910 trillion won.

Semiconductors and large-cap IT stocks led the declines. The electrical and electronics sector was at the center of the index drop. The stocks that had driven repeated record highs fell the most.

On KOSDAQ, robots and secondary batteries were weak. Rainbow Robotics recorded an intraday -9.77%, and Ecopro BM recorded an intraday -7.62%. Autos were also sluggish, with Hyundai Motor falling in the 8% range.

Because it was a sharp selloff, weakness spread across most sectors, and no clear strong sector was confirmed.

SK hynix 2,555,000 won -12.47%. It was the largest drop since 2008년 12월. The market-cap No. 1 position it had taken from Samsung Electronics yesterday was shaken in just one day.

Samsung Electronics 310,000 won -12.31%. It was the largest drop since 2008년 10월.

Samsung Electro-Mechanics 1,990,000 won -10.68%.

Hyundai Motor fell in the 8% range.

SK Group stocks, which had been strong the previous day after SK hynix became No. 1 by market capitalization, were pulled into today’s reversal.

Overnight, the U.S. Nasdaq fell 1.32%, spreading weakness in technology shares to Asia. Concerns over AI investment costs and doubts about profitability led to profit-taking in Big Tech. (https://www.cnbc.com/2026/06/22/stock-market-today-live-updates.html)

Ahead of Micron’s earnings announcement on 6월 24일, caution grew over a slowdown in memory demand. This spurred selling in large-cap semiconductor stocks. (https://www.fnnews.com/news/202606231606013826)

Korea again failed to be included in the MSCI developed markets index, cooling expectations for foreign investor flows. (https://www.fnnews.com/news/202606231827107373)

Bank of America revised its Federal Reserve rate outlook from no change this year to three hikes. It reflected the hawkish stance of new Chair Warsh and entrenched high inflation. (https://www.etoday.co.kr/news/view/2596440)

Analysis said the short-gamma effect from the expansion of single-stock leveraged ETFs had amplified volatility. Political discussions over taxing unrealized gains also weighed on investor sentiment. (https://www.fnnews.com/news/202606231606013826)

Sell-side sidecars in the 오전 11시대 and a circuit breaker at 오후 2시33분 were triggered in sequence. (https://www.mt.co.kr/stock/2026/06/23/2026062314313515785)

Han Ji-young, researcher at Kiwoom Securities (quoted by media), said this was “a short-term side effect of crowding, in which money had flowed only into semiconductor stocks, and a technical issue of speed and concentration rather than a fundamental negative. Waiting on the sidelines is more realistic than joining the selling.” His diagnosis was that today’s drop resulted from money that had been concentrated in one area, semiconductors, exiting all at once.

Lee Kyung-min, researcher at Daishin Securities (quoted by media), analyzed that “profit-taking emerged from large-cap semiconductor stocks that had led the rise, turning the index weaker, and these stocks led the broader market decline.” This aligns with the supply-demand picture in which selling was concentrated in the electrical and electronics sector.

Kim Seok-hwan, researcher at Mirae Asset Securities (quoted by media), assessed it as “only a technical correction, not a fundamental negative.” Still, he cited caution over Micron earnings, the failure of MSCI inclusion, and the possibility of further Fed tightening as volatility factors.

Common ground: All three viewed the primary cause of this selloff as technical and flow-driven factors, namely crowding in large-cap semiconductor stocks and profit-taking.

Difference: Kiwoom and Mirae Asset lean toward waiting on the sidelines because fundamentals remain intact, while the macro camp, including BofA’s forecast of three Fed hikes and the failure of MSCI inclusion, sees structural burdens accumulating.

Link to tomorrow: Micron’s earnings on 6월 24일 and the movement of U.S. technology stocks will determine whether fundamental concerns were exaggerated or real.

Trading was halted intraday by the circuit breaker, and KOSPI closed unchanged from its day’s low. From 15:30 to 19:50, no after-hours single-price sharp moves or major post-market disclosures that would change the market direction were confirmed. No major disclosures.

USD/KRW closed at 1,539.1 won. It rose 2.1 won (+0.14%) from the previous session and broke above 1,540 won intraday, the highest in about two weeks (Seoul foreign exchange market close).

The previous U.S. close on 6/22(Mon) was Dow +0.29%, S&P500 7,472.79 -0.37%, and Nasdaq 26,166.60 -1.32%.

Confirmed values for today for DXY, WTI, Brent crude, gold, Bitcoin, and European indexes were limited at this point.

As of 5:30 a.m. U.S. Eastern time, S&P500 futures were -1.33%, Nasdaq100 futures were -2.42%, and Dow futures were about -319 points (-0.61%). Weakness in semiconductors and technology stocks was reflected directly in futures. Confirmation of stock-by-stock premarket figures was limited. (https://www.cnbc.com/2026/06/22/stock-market-today-live-updates.html)

1. Micron earnings and guidance on 6/24. Whether concerns over slowing memory demand are confirmed.

2. Overnight closes for the U.S. Nasdaq and Philadelphia Semiconductor Index. Whether technology-stock selling calms down or continues.

3. Rebound or further decline in SK hynix and Samsung Electronics. The No. 1 market-cap position and the direction of foreign investor flows.

4. The USD/KRW 1,540 won line and comments from foreign exchange authorities. Whether the exchange rate further stimulates foreign selling.

5. Whether individuals’ net buying in the 8 trillion won range continues, and the burden from margin loans and forced liquidation.

• Today’s closing prices for DXY/WTI/Brent crude/gold/Bitcoin: investing.com and other sources were searched, but confirmed values as of 6/23 were not confirmed.

• Today’s closes for major European indexes: not collected because markets were still trading as of 19:50.

• KOSPI200 and KOSDAQ150 index values: confirmed 6/23 figures were not found in searches.

• Premarket percentage changes for major U.S. large-cap stocks: only index futures were confirmed, while stock-by-stock figures were not finalized.

KOSPI historical data (6/23 close 8,203.84): https://kr.investing.com/indices/kospi-historical-data

KOSDAQ historical data (6/23 close 891.52): https://kr.investing.com/indices/kosdaq-historical-data

Foreign and institutional selling of 4 trillion won, sidecar triggered (Financial News): https://www.fnnews.com/news/202606231203219904

KOSPI plunges 9.9% on foreign and institutional selling (Financial News): https://www.fnnews.com/news/202606231827107373

Analysis of causes behind Black Tuesday’s record drop (Financial News): https://www.fnnews.com/news/202606231606013826

Samsung Electronics and SK hynix plunge in the 12% range, worst since the financial crisis (Etoday): https://www.etoday.co.kr/news/view/2596502

KOSPI down 9.99% and KOSDAQ down 7.94%, exchange rate at 1539.1 won (Etoday): https://www.etoday.co.kr/news/view/2596447

FX close, intraday break above 1540 won (Etoday): https://www.etoday.co.kr/news/view/2596440

Level 1 circuit breaker triggered, 4th this year (Money Today): https://www.mt.co.kr/stock/2026/06/23/2026062314313515785

Simultaneous KOSPI and KOSDAQ sell-side sidecars (Money Today): https://www.mt.co.kr/stock/2026/06/23/2026062311500352373

Black Tuesday 9.99% plunge (Korea Economic Daily): https://www.hankyung.com/article/2026062331746

Nasdaq futures plunge, KOSPI down 10% (CNBC): https://www.cnbc.com/2026/06/22/stock-market-today-live-updates.html