Korean Semiconductor Stocks Plunge 10% Following US Election Results and Broad Market Sell-Off

Investors began November 2026 with growing skepticism regarding financial returns on massive capital expenditures for artificial intelligence infrastructure. This uncertainty deepened after the November 3, 2026, US midterm elections. The Democratic Party secured control of both the US Senate and the House of Representatives for the remainder of President Donald Trump's term.

Leading up to the market volatility, voters in 10 states considered 41 local ballot measures intended to restrict the construction of data centers. Voters rejected these proposed projects in all but one instance.

1. The Kospi index triggered a circuit breaker on November 5, 2026, to curb panic selling.

2. The Philadelphia Semiconductor Index fell by more than 12% during the recent market downturn. This index tracks the performance of 30 of the largest companies involved in semiconductor production.

3. The share price of South Korean chipmaker SK Hynix fell 11.5% on November 5, 2026. Samsung shares also declined by nearly 10% in that same trading session.

4. The Nikkei 225 index in Japan fell 6% during early trading on November 5, 2026. Kioxia shares dropped 12.6%. Tokyo Electron shares declined 9.5%.

5. Taiwan's Taiex index fell by more than 8.3% on November 5, 2026. Chipmaker TSMC shares dropped by nearly 8.5% during the broader regional market decline.

6. The tech-heavy Nasdaq composite index fell more than 5.5% after the US midterm election results. The drop wiped out an estimated $2.5tn (£1.9tn) in market value. Election results confirmed that Democrats won both the US Senate and the House of Representatives.

1. Market analysts noted that the sell-off was exacerbated by the US midterm election results, which raised concerns on Wall Street. These results contributed to the broader tech-sector decline that impacted global chipmakers.

2. Voters in 10 US states weighed in on 41 local ballot measures concerning data center development on November 3, 2026. Of those measures, 28 sought to restrict or halt construction through outright bans, moratoriums, or stricter zoning rules, reflecting local resistance that threatens the pace of physical AI infrastructure expansion.

3. A Democratic majority in both chambers of the US Congress increased investor expectations of stricter federal oversight on artificial intelligence development and energy consumption. Analysts stated that tougher regulatory scrutiny on US data center projects directly threatens hardware demand from Asian memory and foundry suppliers.

4. Major US semiconductor companies experienced steep single-day losses alongside Asian chipmakers during the downturn. Nvidia shares fell more than 9%, erasing over $400 billion in market capitalization, while AMD and Micron shares both dropped by more than 17%, and SanDisk fell 22%.

5. Corporate earnings headwinds compounded the post-election semiconductor sell-off. Qualcomm shares slid more than 9% on November 5, 2026, after the company issued a weaker-than-expected profit forecast and reported slowing smartphone chip sales due to memory chip shortages.

6. The Korea Exchange activated a sell-side sidecar on November 5, 2026, after the KOSPI fell 4.67% to 5,418.15 in morning trading. The emergency mechanism suspended program trading for five minutes to curb panic selling as foreign investors withdrew capital from South Korean memory chipmakers.