[2026.07/27~07/31] Korea Stock Market Weekly Review | US-China Chip Shock, Circuit Breaker Crash & Foreign 18% Rebound
📊 This Week at a Glance
The final week of July (7/27–07/31) delivered one of the most extreme bouts of volatility the Korean stock market has ever seen — a single week that packed in both a circuit breaker crash and a record-scale surge. A US-China semiconductor shock sent the KOSPI tumbling for three straight sessions to the 5,500 level, but on the final trading day foreign investors poured in roughly 7 trillion won of net buying, driving a one-day +17.91% explosion that recovered most of the losses. On a weekly basis, however, both indices still closed lower — KOSPI -3.10% and KOSDAQ -5.36%.
| Index | Weekly Open | Weekly Close | Weekly High | Weekly Low | Weekly Change | Weekly Volume |
|---|---|---|---|---|---|---|
| KOSPI | 6,806.27 | 6,595.45 | 6,806.27 | 5,262.77 | -3.10% | 187,766.8만 |
| KOSDAQ | 760.54 | 719.76 | 780.39 | 630.99 | -5.36% | 246,219.6만 |
The USD/KRW exchange rate spiked to as high as 1,472 won intraday during the sell-off, but as risk appetite recovered it stabilized back toward a weekly close of around 1,442.07 won.
📅 Daily Performance
This week's day-by-day path was a genuine roller coaster: a firm start on Monday, three consecutive days of steep declines from Tuesday, and a record-scale rebound to finish on Friday.
| Date | KOSPI Close | KOSPI Change | KOSDAQ Close | KOSDAQ Change |
|---|---|---|---|---|
| 07/27 (Mon) | 6,755.75 | +0.97% | 764.86 | +2.22% |
| 07/28 (Tue) | 6,023.66 | -10.84% | 705.85 | -7.72% |
| 07/29 (Wed) | 5,663.24 | -5.98% | 662.68 | -6.12% |
| 07/30 (Thu) | 5,593.56 | -1.23% | 644.78 | -2.70% |
| 07/31 (Fri) | 6,595.45 | +17.91% | 719.76 | +11.63% |
On July 28 in particular, the US-China chip shock triggered a simultaneous circuit breaker on both the KOSPI and KOSDAQ markets, and a sell-side sidecar was activated shortly after the open as panic spread across the market. In stark contrast, on July 31 a semiconductor blow-off saw the KOSPI vault nearly 18% in a single day to reclaim the 6,500 level.
📈 KOSPI Weekly Analysis
The KOSPI opened the week around 6,806pt, but on July 28 the US-China semiconductor shock drove a one-day -10.84% plunge that tripped the circuit breaker, with the index barely holding the 6,000 line. It then fell for three straight sessions — July 29 (-5.98%) and July 30 (-1.23%) — sliding to an intraday low of 5,262pt and a closing low of 5,593pt.
On the final trading day of July 31, however, foreign investors stepped in with roughly 7 trillion won of net buying spanning cash equities, futures and ETFs, powering a one-day +17.91% surge to close at 6,595pt — recovering the bulk of the week's losses. On a weekly basis the index still finished -3.1% lower, but the daily swings marked some of the widest in history in a true roller-coaster market. Ultimately, the direction of flows into the semiconductor mega-caps dictated the entire index for the week.
📉 KOSDAQ Weekly Analysis
The KOSDAQ moved in lockstep with the KOSPI, posting equally violent volatility. It opened strong at 764pt (+2.22%) on July 27, but plunged -7.72% on July 28 as a companion circuit breaker was triggered, and slid further on July 29 (-6.12%) and July 30 (-2.70%) to an intraday low of 630.99pt.
On July 31, warmth spread from semiconductor materials-parts-equipment (SMPE) suppliers to pharma and bio names, driving an +11.63% rebound to close at 719pt. The KOSDAQ's weekly change of -5.36% was a larger loss than the KOSPI's, reflecting how the greater volatility of small- and mid-cap growth names amplified the decline. During the rebound, semiconductor SMPE names such as Tes, Techwing, TSE and Simmtech surged to daily limit-ups and led the recovery.
🔥 Weekly Themes & Sectors
By sector, the semiconductor value chain dominated the leaderboard for the week — largely the result of flows concentrated in the final-day blow-off rally. (Sector data shown reflects the aggregated market ranking.)
| Rank | Sector | Weekly Change |
|---|---|---|
| 1 | Semiconductors & Semiconductor Equipment | +28.03% |
| 2 | Electronic Equipment & Instruments | +26.79% |
| 3 | Electrical Equipment | +21.18% |
| 4 | Conglomerates | +16.75% |
| 5 | Life Insurance | +16.69% |
| 6 | Telecom Equipment | +15.13% |
Key Rising Themes
- Semiconductor & SK Hynix Leverage (Up): Led the final-day rebound. TIGER 200 IT Leverage, KODEX Semiconductor Leverage, and the SOL / TIGER / RISE SK Hynix single-stock leverage products surged en masse, many hitting the daily limit-up. Foreign investors' concentrated buying of the semiconductor mega-caps was the engine of the rebound.
- Semiconductor SMPE (KOSDAQ) (Up): Tes (limit-up), Techwing (limit-up), TSE (limit-up), Simmtech (limit-up), Samyang NC Chem, MK Electron and Jeju Semiconductor all joined a limit-up parade during the rebound. The warmth from the mega-cap recovery spread broadly across back-end and materials names.
- Pharma & Bio (Up): A sector that shared in the July 31 rebound alongside semiconductors, contributing to the KOSDAQ's recovery.
Key Falling Themes
- Inverse & Double-Inverse ETFs (Down): SOL SK Hynix Futures Inverse 2X hit the daily limit-down, while Mirae Asset / Hana / Kiwoom Inverse 2X Semiconductor ETNs and the KODEX / TIGER 200 Futures Inverse 2X products dominated the biggest decliners. The losses were amplified because the rebound coincided with the first day of new leverage-product regulations.
💰 Foreign & Institutional Weekly Flow
The single most important driver of flows this week was, without question, foreign investors. During the US-China chip shock on July 28, foreigners unloaded a massive wave of selling centered on the semiconductor sector, triggering the circuit breaker and sidecar and driving the USD/KRW rate to an intraday spike of 1,472 won.
Yet on the final trading day of July 31, foreign investors bought across the board — cash equities, index futures, single-stock futures and ETFs — for roughly 7 trillion won of net buying, powering the +17.91% surge. Both the crash and the rebound hinged decisively on foreign flows, and the defining feature of the week was how such an extreme reversal in direction unfolded within a single day. (Detailed institutional flow figures were not included in this week's data collection.)
🌍 Global Impact
US equities closed the week firmly higher.
| Index | Close | Change |
|---|---|---|
| S&P 500 | 7,489.72 | +0.70% |
| NASDAQ | 25,373.85 | +1.00% |
| Dow Jones | 52,485.03 | +0.53% |
This was a week packed with global monetary-policy events. On July 30 the FOMC was expected to hold the federal funds rate at 3.75%, with the US Q2 advance GDP reading (forecast +2.1%) and Core PCE released the same day. The UK's BOE meeting fell on the same day, followed by the Bank of Japan's policy meeting on July 31. Because the direct trigger for Korea's semiconductor plunge was a US-China chip-related shock, sensitivity to external variables was extraordinarily high throughout the week.
📋 This Week's Economic Indicators & Earnings
Major Global Economic Indicators (High Impact)
| Date (KST) | Country | Event | Forecast / Previous | Actual |
|---|---|---|---|---|
| 07/28 | AUD | RBA Gov Bullock Speaks | - / - | TBD |
| 07/29 | AUD | CPI m/m | 0.2% / -0.7% | TBD |
| 07/29 | AUD | CPI y/y | 4.0% / 4.0% | TBD |
| 07/30 | USD | Federal Funds Rate (FOMC) | 3.75% / 3.75% | TBD |
| 07/30 | USD | FOMC Statement & Press Conference | - / - | TBD |
| 07/30 | USD | Advance GDP q/q | 2.1% / 2.0% | TBD |
| 07/30 | USD | Core PCE Price Index m/m | 0.2% / 0.3% | TBD |
| 07/30 | GBP | BOE Official Bank Rate & MP Report | 3.75% / 3.75% | TBD |
| 07/31 | JPY | BOJ Policy Rate & Outlook Report | <1.00% / <1.00% | TBD |
| 07/31 | CAD | GDP m/m | 0.2% / 0.5% | TBD |
* Actual release figures could not be confirmed from the news feed and are therefore marked "TBD." This was a genuine "super week" with the FOMC, BOJ and BOE meetings all clustered into a single stretch.
Major Domestic Disclosures
No major DART disclosures were captured in this week's data collection.
Earnings-Related Issues
The core force that shook the market this week was the resurgent semiconductor peak-out narrative, which flared up in tandem with Samsung Electronics' earnings release. Even an earnings beat that topped market forecasts was met with sharp share-price declines, as fears of an AI CAPEX peak-out fueled semiconductor liquidation. Large-scale bargain hunting by foreign investors on the final trading day then powered a successful reversal.
🔮 Next Week Outlook & Key Risks
Next week (early August) is expected to be about digesting the follow-through market reaction to the FOMC, BOJ and BOE policy decisions that were clustered this week. The tone of the FOMC's rate hold (3.75%) and Chair Powell's press conference, along with the BOJ's policy stance, will be key focal points for their impact on the currency and on foreign flows.
Domestically, the subsequent price action of the semiconductor mega-caps (Samsung Electronics and SK Hynix), the direction of foreign trading, and early-August macro readings such as US employment data are the variables that will determine whether volatility re-expands. With the close having recovered so sharply from the weekly intraday low of 5,262pt, the sustainability of the sharp rebound is the single biggest question for next week. (Specific next-week schedule data was not included in this collection, so investors should confirm the official release calendar.)
Key risks to watch include:
- The possibility of a repeat crash like this week's if US-China semiconductor risk reignites
- Short-term overheating and profit-taking pressure following a single-day +17.91% surge
- The structural fragility of an index excessively tethered to a single semiconductor sector
- The risk of renewed volatility should foreign flows sharply reverse again
- Pressure from potential foreign capital outflows if the USD/KRW rate entrenches in the 1,440-won range
- Flow distortions and derivative volatility stemming from the newly enforced leverage regulations
⚠️ Investment Disclaimer
Disclaimer: This post is for informational purposes only and does not constitute investment advice. All investment decisions are the sole responsibility of the investor. Past performance does not guarantee future results.
🇰🇷 Korean Version: https://kai-search.tistory.com/manage/posts/
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