KOSPI Bear Market: How $500 Billion in Margin Calls, Chip Concentration, and the Kyber Delay Shook Global Stocks

In 2026, South Korea's KOSPI underwent one of the most dramatic reversals in modern market history. After being the world's best-performing major index, it plunged into bear market territory within weeks, wiping out hundreds of billions in value and sending shockwaves through global chip and AI stocks. The collapse was not a single event but a collision of three forces: record retail leverage that triggered forced margin calls, extreme concentration risk in just two stocks (Samsung Electronics and SK Hynix), and macro shocks from rising Middle East tensions. A disputed report about Nvidia's Kyber NVL144 AI server rack delay added further uncertainty. Here is the verified breakdown of what happened, supported by cited sources.

Three Causes of the KOSPI Bear Market

The KOSPI reached the brink of bear-market territory after a sharp selloff from a record high. Bloomberg reported that a 4.3% drop extended the decline from a late-February record to nearly 20%, the threshold typically considered a bear market . Another report described a later nearly 10% one-day crash after an unverified report concerning SK Hynix's HBM4 schedule, saying the episode exposed how concentrated and leverage-loaded the index had become .

Chip concentration risk. South Korean stocks tumbled from record highs as investors sold off chip heavyweights . Samsung Electronics and SK Hynix together account for over 50% of the KOSPI's weighting and nearly 75% of its 2026 gains . When these two stocks fell, they dragged the entire index down with them. One analyst report singled out the SK Hynix-related news as exposing the concentration risk in the index .

Record retail leverage. Forced liquidations of retail investors' leveraged positions reached nearly 500 billion won over three days, as individual investors' debt-financed investments swelled to a record high . The volume snowballed particularly on Friday and Monday, when the KOSPI plunged 5.54% and 8.29%, respectively. A significant portion of the increase in margin loans was concentrated in AI-related market leaders . The Korea Exchange triggered multiple trading halts and circuit breakers .

Macro shocks. Rising Middle East tensions drove oil prices higher, fueling inflation concerns and damping risk appetite in the tech-heavy market . The escalation in Iran-Israel tensions created a global risk-off sentiment that hit the most crowded trades first . CNBC attributed the volatility to investors reevaluating risks from the escalating conflict in the Middle East alongside the market's heavy reliance on a limited number of stocks .

The Forced-Liquidation Channel: Did Korean Margin Calls Bring Down Nvidia?

The available sources support a forced-liquidation channel in Korea, but they do not verify the more specific claim that Korean margin calls alone caused Nvidia to lose roughly $1 trillion in market value. Forced liquidations in Korea reached nearly 500 billion won over three days, and the selloff was concentrated in chip-heavy parts of the market . That kind of liquidation pressure plausibly contributed to broader risk-off sentiment around semiconductor and AI-linked equities. One research note from Bloodstone Capital described the KOSPI's 8.29% plunge on June 8 as 'its worst day since pandemic lows,' triggered by a convergence of US payroll data, spiking Treasury yields, and renewed Iran-Israel missile exchanges that caused forced deleveraging across the region's AI and semiconductor complex . Another analysis from MEXC argued the crash was 'a forced liquidity extraction by global macro hedge funds using Korea as an ATM to cover positions elsewhere' . However, the supplied sources do not establish a precise causal chain from Korean margin calls to a specific Nvidia market-cap decline.

The Kyber NVL144 Delay: Fact, Fiction, and Market Impact

On July 6, 2026, semiconductor research firm SemiAnalysis posted on X that Nvidia's next-generation Kyber NVL144 rack architecture had been delayed by more than 12 months to 2028 due to manufacturing challenges with its core PCB midplane component . SemiAnalysis also stated that the NVL72x2 back-to-back rack architecture had been canceled . The Kyber NVL144 system is designed to connect 144 high-performance chips in a single rack and was expected to arrive alongside Nvidia's Vera Rubin Ultra platform in 2027 . The reported delay was attributed to a 78-layer PCB midplane manufacturing yield problem .

Nvidia pushed back against the report. In a statement covered by multiple outlets, Nvidia said its product roadmap remains on schedule . The stock remained in focus after the denial, but it lagged a broader semiconductor rally—rising only 0.5% to 0.8% while the Philadelphia Semiconductor Index surged 3.2% and rivals AMD and Broadcom gained 7.7% and 4.4% respectively .

Verdict: The unconfirmed Kyber NVL144 delay report added uncertainty around Nvidia's roadmap, but Nvidia denied the claim. The available sources support the Korea-centered leverage unwind as the better-supported primary driver, with the Kyber report acting as an additional stock-specific overhang rather than the sole cause .

Wall Street Consensus: Fundamental Reassessment or Forced Liquidation?

The supplied sources do not substantiate a full Wall Street consensus that the decline reflects a fundamental reassessment of AI spending. The evidence supports a more nuanced picture.

Goldman Sachs remained bullish on Nvidia. In May 2026, Goldman Sachs analyst James Schneider reiterated a Buy rating and raised his 12-month price target on Nvidia to $285 from $250, applying an unchanged 30x multiple to a normalized EPS estimate that he lifted to $9.50 from $8.25 . Schneider wrote that Goldman sees 'a clearer path for the stock to outperform the market over the coming months,' driven by upside to hyperscaler CapEx forecasts and Nvidia's improved capital allocation framework . Earlier, in February 2026, Goldman Sachs set a Nvidia price target of $250 per share, representing a 35% increase from the closing price, with revenue and EPS estimates of $215.1 billion and $4.49 for 2026, and $382.9 billion and $8.25 for 2027 . Following the GTC 2026 event, Goldman reaffirmed its $250 target with a Buy rating, while Bernstein set $300 and Morgan Stanley $260 . By June 2026, Goldman confirmed a target of $285 .

Nvidia's valuation compressed dramatically. By March 2026, Nvidia was trading at a forward P/E of approximately 19.7 times, below the S&P 500's 20.3 times—the first time in more than 13 years that Nvidia had not traded at a premium to the broader index . By July 2026, Nvidia's forward P/E had fallen to 18.69x, less than half its 10-year average of 36.9x and the lowest level in 11 years . TheStreet noted that even as Nvidia's earnings continued to grow, its stock was in a six-month funk, with one theory being that 'the company's most significant hurdle may now be its sheer scale' .

The Korea evidence points to forced liquidation. Forced liquidations of leveraged retail positions reached nearly 500 billion won over three days, and the selloff was tied to volatile markets, Middle East tensions, and a sharp move against leveraged investors . One analyst described the Korea open as 'not a normal risk-off move' but rather 'forced de-risking, not patient institutional selling' .

Supported conclusion: The available evidence more clearly documents a forced liquidation event in Korea and a disputed Nvidia roadmap scare than it documents a broad fundamental reassessment of AI infrastructure spending . Goldman's cited bullishness supports the idea that at least some Wall Street coverage remained constructive on Nvidia's AI prospects. The compression of Nvidia's forward P/E to pre-AI boom levels, combined with rising earnings forecasts, created a valuation disconnect that some analysts viewed as an opportunity rather than a signal of structural weakness .