KOSPI Plunges 5.5% on Black Friday, Sidecar Triggered as Broadcom Outlook Drags Asian Tech Stocks

Published June 6, 2026 | Covers the June 5, 2026 Asian market sessions | Economy News | ECONPLEX Editorial Desk

Asia’s stock markets experienced a sweeping technology-driven sell-off on Friday, June 5, 2026. The regional downturn was triggered by a disappointing artificial intelligence (AI) chip revenue forecast from U.S. semiconductor giant Broadcom during the previous Wall Street session, which prompted global investors to aggressively re-evaluate high-flying tech valuations. South Korea’s benchmark KOSPI led the declines, enduring a historic “Black Friday” plunge that triggered an intraday sell-side sidecar, while markets in Tokyo, Hong Kong, Taipei, and Shanghai all finished in the red.

South Korea: “Black Friday” Tech Rout Triggers Program Trading Suspension

The South Korean market suffered the brunt of the regional tech rout. The benchmark KOSPI plummeted 478.82 points, or 5.54%, to close at 8,160.59, marking its largest single-day percentage decline since mid-May, according to Morningstar. High-growth and tech-heavy shares on the KOSDAQ fell in tandem, reflecting widespread risk aversion.

The morning sell-off was so severe that the Korea Exchange (KRX) activated a sell-side sidecar at 9:08 a.m. KST, suspending program sell orders for five minutes, as reported by The Korea Times. The mechanism is triggered when the KOSPI 200 futures contract drops by 5% or more and remains there for over a minute; Friday’s event marked the 10th time the sidecar had been activated in 2026.

South Korea’s two primary semiconductor giants bore the heaviest selling pressure:

SK Hynix (000660): The memory maker slumped 9.92% to close at 2,070,000 KRW, facing intense selling as investors locked in profits following its massive Q1 earnings run.
Samsung Electronics (005930): The tech bellwether closed down 6.40% at 329,000 KRW.

Market analysts noted that the presence of leveraged single-stock exchange-traded funds (ETFs) contributed to the day’s sharp volatility, forcing automated rebalancing that accelerated the downward spiral as semiconductor prices fell, according to Seoul Economic Daily.

Japan and Taiwan: Semiconductor Heavyweights Drag Indices Lower

In Tokyo, the Nikkei 225 declined by 882.57 points, or 1.31%, to finish at 66,588.12, per Trading Economics. Semiconductor manufacturing equipment maker Tokyo Electron Ltd. (8035) led the index’s decline, dropping more than 6% to close at 59,710 JPY as Japanese investors aligned with the global chip sector reassessment.

Taiwan’s Stock Exchange (TAIEX) also experienced a highly volatile session, swinging widely before closing down 606.52 points, or 1.33%, at 45,070.94, according to Focus Taiwan. Benchmark heavyweight TSMC (2330.TW) fell NT$20.00, or 0.84%, to NT$2,365.00. While TSMC recovered some intraday losses due to late-session support, CEO C.C. Wei’s comments reminding the market of long-term supply constraints for AI chips did little to fully offset the global tech headwind.

China and Hong Kong: Hang Seng Falls Below 25,000

Chinese and Hong Kong markets were not immune to the technology drag. Hong Kong’s benchmark Hang Seng Index slipped 291.45 points, or 1.15%, to close at 24,961.95, falling below the psychologically important 25,000-point threshold, according to Morningstar.

In mainland China, the benchmark Shanghai Composite Index fell 30.04 points, or 0.74%, to close at 4,027.74. The blue-chip CSI 300 index experienced a steeper decline of 1.79%, ending the session at 4,816.92, according to the Shanghai Stock Exchange, as tech-related components in mainland indices faced selling pressure.

India: Sensex Edges Lower as RBI Holds Rates and Adjusts Economic Forecasts

India’s BSE Sensex finished down 0.16% at 74,243 points, recovering from earlier intraday gains, according to Investing.com. The session was dominated by the Reserve Bank of India’s (RBI) monetary policy announcement. The RBI unanimously voted to keep the repo rate unchanged at 5.25% and maintained its “neutral” stance, as reported by The Hindu.

However, the central bank’s updated economic forecasts introduced caution. Citing geopolitical tensions in the Middle East and elevated commodity prices, the RBI lowered its FY27 GDP growth projection to 6.6% (from 6.9%) and raised its CPI inflation forecast to 5.1% (from 4.6%). To counter capital outflows, the RBI announced higher investment limits for non-resident Indians (NRIs) and expanded access to long-term government bonds.

Other Asian Markets and Global Macro Context

Singapore STI: Closed down 0.35% at 5,049.96, dragged down by regional tech weakness and financial-sector caution.
Australia S&P/ASX 200: Finished 61.0 points lower, or 0.70%, at 8,625.10, marking its second consecutive daily loss.
Commodities: Brent crude futures traded around $95.45 per barrel, keeping energy costs elevated due to the effective closure of the Strait of Hormuz. Spot gold (XAU/USD) traded near $4,470 per ounce under pressure from a stronger dollar.
Global Yields: Following the Asian market close, the U.S. Bureau of Labor Statistics released a stronger-than-expected May jobs report, showing 172,000 nonfarm payroll additions (well above the 85,000 forecast) and an unchanged 4.3% unemployment rate. This strong economic data pushed the U.S. 10-year Treasury yield up to 4.54%, which is expected to influence Asian market openings next Monday.

What Investors Should Watch Next Week

U.S. Jobs Report Impact on Yields: The stronger U.S. payroll report and subsequent jump in the U.S. 10-year yield to 4.54% will test global tech stock valuations when Asian markets reopen on Monday.
Semiconductor Sector Stabilization: Investors will watch whether SK Hynix, Samsung, and Tokyo Electron can establish support levels after Friday’s sharp capitulation.
Geopolitical Developments: Any changes in Middle East shipping corridors or progress on U.S.-Iran diplomatic talks will immediately impact Brent crude and trade balances for net-importing Asian economies.

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