KOSPI falls 2.67% as AI spending worries hit Samsung, SK hynix

Key takeaways

• The KOSPI was down 2.67% at 5,702.5 at 00:03 UTC on Tuesday, Nov. 3, 2026, according to Yahoo Finance data, after a 2.46% drop at the opening bell.
• Yonhap linked the selloff to lingering worries over heavy AI infrastructure spending ahead of the U.S. midterm elections.
• Samsung Electronics and SK hynix each fell more than 4% at the start of the session, Tokenpost reported.
• The drop erased Monday's 2.24% rebound, which had lifted the index to 5,859.08 on institutional buying.

South Korea's benchmark KOSPI fell 2.67% to 5,702.5 by 00:03 UTC (09:03 KST) on Nov. 3, Yahoo Finance data showed. Chip heavyweights led the decline as worries about AI spending returned ahead of the U.S. midterm elections.

The fall more than wiped out Monday's gain, leaving the index below its Oct. 30 close of 5,730.74. For investors in Southeast Asia, Seoul is often an early read on how chip and AI-linked shares will trade in the region later in the day.

What happened to the KOSPI on Nov. 3

The KOSPI opened down 143.89 points, or 2.46%, at 5,715.19 when trading began at 09:00 KST (00:00 UTC), according to Yonhap, as carried by K-VIBE, and Seoul Economic Daily. The selling continued in the first minutes. By 00:03 UTC, Yahoo Finance data showed the index 156.58 points, or 2.67%, below Monday's close.

Semiconductor stocks, the largest weights in the index, led the decline. Samsung Electronics and SK hynix each traded more than 4% lower at the start of the session, according to a Tokenpost report timestamped 00:02 UTC. Tokenpost did not give share prices.

Why the KOSPI fell: what the reports say

Yonhap reported that South Korean stocks "started sharply lower Tuesday," weighed down by "lingering concerns over massive spending on artificial intelligence (AI) infrastructure" ahead of the U.S. midterm elections. Yonhap also noted that oil prices had fallen on optimism about a possible U.S.-Iran peace agreement.

The lead came from Wall Street's mixed session on Monday, Nov. 2. CNBC reported that the Nasdaq Composite fell 1.07% to 25,164.32 and the S&P 500 slipped 0.51% to 7,541.40, while the Dow Jones Industrial Average gained 0.41% to 51,983.98. Yahoo Finance's live coverage said investors "continued to rotate out of technology names ahead of the mid-term elections on Tuesday."

Several U.S. tech names fell sharply on deal and funding news. According to CNBC:

• Marvell shares fell almost 13% and Lumentum lost 18% after Marvell agreed to buy Lumentum in a deal valued at $115 billion.
• Oracle fell about 8% after saying it would sell $10 billion in common stock and $10 billion in senior notes to fund its AI buildout.

Both moves added to questions about how AI investment will be financed.

No report seen by Bullquill as of 00:25 UTC gave a Korea-specific trigger for Tuesday's drop. The causes above are the ones attributed by the reports cited; investor flow data for the session were not yet available.

What we know and what we don't know yet

Confirmed

• The KOSPI opened 2.46% lower at 5,715.19 (Yonhap; Seoul Economic Daily).
• The index was down 2.67% at 5,702.5 at 00:03 UTC (Yahoo Finance).
• Samsung Electronics and SK hynix were each down more than 4% at the open (Tokenpost).

Not yet known

• Whether foreign or institutional investors drove the selling on Tuesday.
• Where the index will close. On Monday, the KOSPI opened 1.62% lower and still ended up 2.24%, so early moves can reverse.
• How the U.S. midterm results and this week's U.S. employment report, both flagged by analysts quoted in The Korea Times, will affect trading.

Background: a volatile week for Korean chip stocks

The KOSPI has swung sharply as AI-related shares were repriced. On Monday, Nov. 2, the index opened 1.62% lower, then reversed to close up 2.24% at 5,859.08, The Korea Times reported. Institutions bought a net 1.36 trillion won of shares, while foreign investors sold a net 43.09 billion won and retail investors sold a net 1.41 trillion won.

Samsung Electronics closed Monday up 1.78% at 229,000 won, and SK hynix rose 3.81% to 1,472,000 won. Lee Kyoung-min of Daishin Securities was quoted by the paper as saying "much of the bad news had already been priced into Korean stocks."

Monday's rebound followed a slide on Friday, Oct. 30, when the KOSPI closed at 5,730.74. Bloomingbit said on Nov. 2 that worries about AI spending had spread from Wall Street after disappointing earnings and guidance from Alphabet, Amazon and Intel. It added that the Philadelphia Semiconductor Index had plunged 7.2% on Oct. 30. Bullquill covered that rout in Nasdaq falls as Intel plunge drives AI chip selloff. Earlier swings are tracked in KOSPI drops 3% as chip stocks follow U.S. selloff and the South Korea stocks weekly brief for Oct. 30.

Oil also fell sharply on Monday. CNBC reported that Brent crude fell 7.63% to $104.77 a barrel at the close on Nov. 2, while WTI settled down 7.36% at $96.46, as hopes grew for U.S.-Iran peace talks. CNBC did not name the Brent contract month; January has been the front-month Brent contract since the December contract expired on Oct. 30.

What it means for ASEAN investors

Seoul's market opens before Southeast Asian exchanges each trading day, so a chip-led fall there is an early signal for AI and semiconductor-linked shares in the region. On Monday, Nov. 2, the same global chip weakness hit Malaysia. The Star reported at 9:28 a.m. MYT that Bursa Malaysia's "technology and semiconductor stocks" were "extending their losses on weaker global sector sentiment." Malaysian Pacific Industries fell 58 sen to RM39.20 and ViTrox fell 22 sen to RM10.68 in early trade. Bullquill's Nvidia stock analysis has more on the link between U.S. and Malaysian chip shares.

Cheaper oil pulls the region in a different direction: it helps net fuel importers but can weigh on energy producers. Its overall effect on ASEAN benchmarks on Nov. 3 is not yet known.

Bullquill's ASEAN Close tracker will show how Southeast Asian benchmarks finish the Nov. 3 session. Whether Seoul's drop carries over will depend on how the KOSPI ends the day and on U.S. midterm results.

This article is for information only and is not investment advice.