KOSPI closes at 6,788.88 on August 28, 2026 — foreigners sell 1.76 trillion won on chip tariff report
The KOSPI index in South Korea closed at 6,788.88 on August 28, 2026, down 123.49 points or 1.79 percent, ending three straight sessions of gains and falling back below the 6,800 line. The trigger was a report that the United States is considering extending semiconductor tariffs to finished goods that contain chips, which sent the country's two memory heavyweights sharply lower: Samsung Electronics fell 3.38 percent and SK Hynix 4.45 percent. Foreign investors sold a net 1.76 trillion won and institutions a net 284.2 billion won, while retail investors were the only net buyers at 424.4 billion won. The KOSDAQ rose 0.09 percent to 838.41 and the won strengthened 8.4 to 1,372.5 per dollar
The three lines
- Index — KOSPI 6,788.88, down 123.49 points or 1.79 percent, ending a three-day advance
- Cause — Report of a second round of US chip tariffs. Samsung minus 3.38 percent, SK Hynix minus 4.45 percent
- Flows — Foreigners sold a net 1.76 trillion won. Only retail investors bought
Key questions
- Where did the KOSPI close on August 28, 2026?
- **6,788.88**, down **123.49 points** or **1.79 percent** from the previous close of 6,912.37. Three straight sessions of gains ended in one day and the index **fell back below 6,800**. The **KOSDAQ**, Korea's secondary board of smaller and technology-heavy listings, moved the other way, rising 0.76 points or **0.09 percent to 838.41**. On flows, **foreign investors sold a net 1.76 trillion won**, institutions sold a net **284.2 billion won**, and **retail investors bought a net 424.4 billion won** — sellers in the trillions, buyers in the hundreds of billions. The won **strengthened 8.4 to 1,372.5** per dollar.
- Why did semiconductors fall so hard?
- **Because Washington is reportedly considering extending chip tariffs to the finished products chips go into.** Politico reported on August 27 US time that the Trump administration is weighing steep tariffs not only on semiconductors themselves but on **data center servers, laptops and game consoles**. The United States already imposed a **25 percent** duty on advanced computing chips on **January 14, 2026** under **Section 232** of the Trade Expansion Act of 1962 — but that round **exempted data center use**. The second round is reported to remove that exemption. For Korea this lands directly: memory chips are the country's single largest export category, and its two makers were named as the most exposed. **Samsung Electronics fell 3.38 percent to 257,000 won** and **SK Hynix 4.45 percent to 1,653,000 won**. The tariff plan is covered separately in "US weighs second round of chip tariffs."
- Why did the KOSDAQ rise while the KOSPI fell?
- **Because the selling was concentrated in two large-cap chipmakers rather than spread across the market.** Samsung Electronics and SK Hynix are the first and second largest companies on the KOSPI by market value, and their combined weight is large enough that a 3 to 4 percent fall in both drags the whole index with it. The KOSDAQ has no memory names of comparable weight. Stocks outside the tariff story saw no selling pressure, and the index finished effectively flat at **838.41, up 0.09 percent**. This publication has covered the same divergence before in "Why the KOSPI fell while the KOSDAQ rose." The rule of thumb: **when two indices in the same market move in opposite directions, look at what they are made of, not at sentiment.**
The KOSPI closed at 6,788.88 on August 28.
That is 123.49 points, or 1.79 percent, below the previous session. Three straight days of gains ended, and the index gave up the 6,800 line.
What pulled it down did not originate in Korea.
1. The numbers
| Item | Value |
|---|---|
| KOSPI close | 6,788.88 |
| Change | −123.49 points (−1.79%) |
| KOSDAQ close | 838.41 (+0.76, +0.09%) |
| Won per dollar | 1,372.5 (−8.4, won stronger) |
The week's path:
| Date | Close | Change |
|---|---|---|
| Aug 24 | 6,696.96 | Samsung Electronics −8.7% |
| Aug 25 | 6,742.74 | +0.68% |
| Aug 26 | 6,808.21 | +0.97% |
| Aug 27 | 6,912.37 | +1.53% |
| Aug 28 | 6,788.88 | −1.79% |
Three sessions recovered 215 points. One session gave back 123.
2. The cause — tariffs reaching finished goods
Politico reported on August 27 US time that the Trump administration is weighing steep tariffs not only on semiconductors but on products containing them.
| Current (round one) | Under review (round two) | |
|---|---|---|
| Effective | January 14, 2026 | Undecided, phased rollout discussed |
| Authority | Section 232 | Section 232 |
| Rate | 25% on advanced computing chips | Undecided |
| Scope | Chips, equipment, derivatives | + servers, laptops, game consoles |
| Data centers | Exempt | Exemption to be scrapped |
For Korea this is not an abstract policy story. Memory semiconductors are the country's largest export category, and the two companies that make them are the two largest listed companies.
| Stock | Change | Close |
|---|---|---|
| Samsung Electronics | −3.38% | 257,000 won |
| SK Hynix | −4.45% | 1,653,000 won |
Thursday's Nvidia-driven gains were erased in a single session.
3. Flows — foreigners sold 1.76 trillion won
| Investor | Net |
|---|---|
| Foreign | −1.76 trillion won (net sell) |
| Institutions | −284.2 billion won (net sell) |
| Retail | +424.4 billion won (net buy) |
Selling in the trillions, buying in the hundreds of billions.
This is the exact inverse of the previous session, when retail investors sold 1.91 trillion won and foreigners and institutions bought 318.2 billion won. The roles flipped in a day.
Foreign selling was concentrated in Samsung Electronics and SK Hynix, which is what made the index fall as much as it did. An index tracks the prices of its heaviest constituents, not the arithmetic of net purchases.
4. Why the KOSDAQ rose
| Index | Center of gravity that day |
|---|---|
| KOSPI | Its two largest names are memory makers — the direct target of the tariff story |
| KOSDAQ | No memory names of comparable weight. No selling pressure arrived |
When two indices in one market move in opposite directions on the same day, the explanation is usually composition, not sentiment.
5. The won strengthened anyway
The won closed at 1,372.5 per dollar, 8.4 stronger than the previous session.
Falling equities often push the local currency weaker; this session did the opposite. One likely factor was still in play from the day before: the Bank of Korea raised its policy rate to 3.00 percent on August 27, narrowing the gap with the US benchmark from 1.00 to 0.75 percentage points. That mechanism is covered in "What the Korea-US rate gap is."
How much of the day's move that accounted for was not isolated here.
6. What was not confirmed
- KOSDAQ and FX — 838.41 and 1,372.5 each rest on a single source.
- Flows — one outlet's figures; totals shift with cut-off time.
- Intraday — high, low and the shape of the drop were not confirmed.
- Breadth — sector moves and advancer-decliner counts were not reviewed.
- Politico — the original report was not read directly.
Sources
- Ajunews — KOSPI closes down 123.49 points (1.79%) at 6,788.88
- The Korea Economic Daily — KOSPI gives up 6,800 on chip weakness; foreigners sell 1.7 trillion won
- Herald Business — Foreign and institutional selling of 2 trillion won drives KOSPI down 1.79%
- Betanews — Samsung and SK Hynix slide on US chip tariff review; KOSPI down 1.79%
- Maeil Ilbo — KOSPI falls 1.79% below 6,800 on semiconductor weakness
- CNBC — U.S. considers fresh round of tariffs on semiconductors, report says