Why Did the Kospi Open 3.17% Lower for EWY (NYSEARCA:EWY) Holders?

Key Highlights

• South Korea's Kospi opened 3.17% lower at 5,488.41 on Monday, October 19, 2026, after its worst week since October 2008, while Japan's Nikkei fell about 1.7% to 64,194.90.
• Taiwan's Taiex fell 1.42% to 46,440.75, a fourth Asian chip selloff in two weeks that fed directly into the US open, where futures were higher in early quotes.
• The open implies a Friday close near 5,668.05, simple arithmetic on 5,488.41 plus 179.64, and the Kospi remains more than 30% higher for the year despite the slide.
• iShares MSCI South Korea ETF (NYSEARCA:EWY) holds South Korean equities, so the Kospi slide matters to US investors in that fund, though no price move for the fund itself is cited here.

The Asian Session

The Kospi opened 3.17% lower at 5,488.41 on October 19, 2026 after the worst week for the index since October 2008. The Nikkei 225 fell about 1.73% to 64,194.90 and the Taiex fell 1.42% to 46,440.75, with chipmakers leading each market. A new DeepSeek model described as faster and more efficient unsettled memory stocks, and China's third quarter data showed gross domestic product growth of 4.5% a year, retail sales up 1.1% and industrial output up 5.5%. Investors watching iShares MSCI South Korea ETF (NYSEARCA:EWY) should note that the Korean market is dominated by a small number of large chip names, so a drop in memory shares moves the whole index. The slide also followed a fall of 7.57% or about 9%, depending on the data set, on October 15.

A Conflict in the Figures

Published figures for the previous week disagree. One data set puts the October 15 Kospi close at 5,554.22, a fall of 7.57%, while another list shows 5,483.65, a fall of about 9%. The Monday open of 5,488.41 implies a Friday close of 5,668.05, simple arithmetic that was used here as a cross-check. Because of the conflict, this article avoids a firm October 15 figure and relies on the worst-week-since-2008 description. The Kospi stayed more than 30% higher for the year, so the fall follows a very large rally, and the iShares fund tagged here tracks MSCI South Korea rather than the Kospi itself, so its moves can differ, and currency changes add a further layer for US investors.

Risks and What to Watch

Korean stocks are exposed to memory prices, foreign fund flows, the Exchange Rate and any change in AI spending expectations. A further fall in SK Hynix and Samsung would hit the Kospi directly because both carry large index weights, and exchange rules can pause trading if moves become extreme, as happened with a circuit breaker earlier in the month. Investors can watch whether the premarket pared losses held, US futures, Micron and Sandisk premarket trading, and chip equipment Earnings on October 21, 2026. The Federal Reserve meets October 27 to 28, and a hawkish tone could hurt Asian markets through the dollar and yields. Nothing in this article is Investment advice.

Where Things Stand

The answer is that Korean chip stocks led the Kospi lower after a fourth Asian chip selloff in two weeks and a new DeepSeek model that unsettled memory makers. The index remains more than 30% higher for the year. For iShares MSCI South Korea ETF (NYSEARCA:EWY) holders, the next checks are whether Monday losses held and how Micron and US chip equipment results on October 21, 2026 are received.