Why Is Monday's Open Uncertain for SOXX (NASDAQ:SOXX), EWY (NYSEARCA:EWY), SPY (NYSEARCA:SPY) and DIA (NYSEARCA:DIA)?

Key Highlights

• The Kospi opened 3.17% lower at 5,488.41 on Monday, October 19, 2026, after its worst week since October 2008, and iShares MSCI South Korea ETF (NYSEARCA:EWY) tracks South Korean equities that led the Asian decline.
• A new DeepSeek model described as faster and more efficient hit SK Hynix by 6.84% and Samsung by 6.03% in early quotes, and iShares Semiconductor ETF (NASDAQ:SOXX) follows US chipmakers that sell into the same chain.
• Nasdaq 100 futures were up 0.7% to 1.3% and S&P 500 futures up 0.4% to 0.8%, depending on provider, before SPDR S&P 500 ETF Trust (NYSEARCA:SPY) opens after the worst week for the Nasdaq since June.
• SPDR Dow Jones Industrial Average ETF Trust (NYSEARCA:DIA) tracks the Dow, which fell 508 points, or 22.6%, on October 19, 1987, but the Dow slipped only 0.34% on Friday, and Black Monday posts are unconfirmed.

iShares Semiconductor ETF (NASDAQ:SOXX): Chip Fund Faces a DeepSeek Headline

A new model from the Chinese AI developer DeepSeek was described over the weekend of October 17 to 18, 2026 as faster and more efficient, and Korean memory stocks fell when trading opened on Monday. SK Hynix lost 6.84% and Samsung Electronics lost 6.03% in premarket quotes on the Nextrade venue at 8:20 a.m. local time, and both later pared their losses. No model name, version number or benchmark was available, so the technical claim cannot be assessed here. SK Hynix and Samsung are listed in Seoul and carry no US tag, while the US-listed chip group is represented by iShares Semiconductor ETF (NASDAQ:SOXX). Both Korean firms are among the largest suppliers of high-bandwidth memory, which is why a single headline about AI efficiency moved them within minutes of the open. Memory makers sell the high-bandwidth chips that AI accelerators use, so any sign that models need fewer chips raises fears for demand. The effect depends on mechanism: if a model needs less memory per task, orders could fall, but cheaper AI can also widen use and raise total demand, a point economists call increased use after efficiency gains. Investors react to the first reading, which is why the stocks fell at the open. TrendForce still expects 2027 high-bandwidth memory selling prices to rise 121%, which contrasts with Monday's fear.

iShares MSCI South Korea ETF (NYSEARCA:EWY): Kospi Opens 3.17% Lower

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. 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.

SPDR S&P 500 ETF Trust (NYSEARCA:SPY): Futures Rebound After Worst Week

Futures on the Nasdaq 100 were up between 0.7% and 1.3% and S&P 500 futures were up between 0.4% and 0.8% in different morning quotes, while the Dow was roughly flat to 0.4% higher. One provider at 5:26 a.m. ET showed the S&P 500 up 0.47%, the Nasdaq 100 up 1.02% and the Dow up 0.02%. The spread reflects different quote times and contract months, so any single number should be read as an indication. SPDR S&P 500 ETF Trust (NYSEARCA:SPY) tracks the S&P 500, which closed Friday at 7,659.44 after a 1.09% decline, and futures changes translate into the fund's opening price only approximately. A rise in futures after a bad week can be a technical rebound as traders cover short positions and as storage stocks bounce, with Micron, Sandisk, Western Digital and Seagate up 2% to 3.8% in one premarket quote, after eight straight losing sessions in the chip group. The market faces headwinds, though. The 10-year Treasury Yield near 5.1% lowers the present value of growth shares, oil above USD 100 raises Inflation worries, and Credit costs for AI borrowers hit records, with Oracle five-year default swaps near 288 basis points.

SPDR Dow Jones Industrial Average ETF Trust (NYSEARCA:DIA): Black Monday Anniversary

On October 19, 1987 the Dow Jones Industrial Average fell 508 points, or 22.6%, according to Federal Reserve history, the largest one-day decline in its history. Analysts later pointed to program trading and portfolio insurance, strategies that sold futures as prices fell and thereby added to selling pressure, along with rising interest rates and a weak dollar. Regulators responded with market-wide circuit breakers and changes to clearing. The history is useful context, but the 2026 market differs in size, structure and rules, and SPDR Dow Jones Industrial Average ETF Trust (NYSEARCA:DIA) trades under today's safeguards. The Dow stood near 2,246 before that session, so the 508-point fall dwarfs any recent daily move, even though modern index levels make point moves look larger. The 2026 market has shown stress but not a collapse. The Nasdaq Composite had its worst week since June, down 4.48%, chip stocks lost eight straight sessions and the VIX rose, with providers quoting a close near 20 and a Monday premarket reading of 18.76. The Dow held up better because energy and defence shares rose, and 21 of 21 energy stocks gained on Friday.

Where Things Stand

The answer is that the open is uncertain because Asian chip stocks fell sharply while US futures point higher, and the quotes differ by provider. iShares Semiconductor ETF (NASDAQ:SOXX) faces the DeepSeek headline. iShares MSCI South Korea ETF (NYSEARCA:EWY) faces the Kospi slide. SPDR S&P 500 ETF Trust (NYSEARCA:SPY) faces a futures rebound after the worst week since June. SPDR Dow Jones Industrial Average ETF Trust (NYSEARCA:DIA) faces Black Monday chatter that carries no predictive value. The 9:30 a.m. ET cash open and Earnings this week will decide whether the rebound holds. Further disclosure from iShares MSCI South Korea ETF (NYSEARCA:EWY) would clarify the picture.