Korean equities endured a second consecutive day of historic selling on Wednesday, as market-wide circuit breakers once again halted trading. Combined with Tuesday's decline, the KOSPI has now fallen nearly 17%, erasing approximately $620 billion in market capitalization over two days — one of the steepest two-day declines in the index's history. The rout prompted South Korea's government to convene an emergency meeting of its financial authorities.

The sell-off was initially triggered by SK Hynix's second-quarter earnings miss. The chipmaker's shares fell an additional 4% on Wednesday, extending the prior session's 15% drop. Together with Samsung Electronics, SK Hynix accounts for nearly half of the Korean benchmark index. Both companies are leading global suppliers of high-bandwidth memory (HBM), the stacked DRAM chips essential to AI accelerators such as NVIDIA's H100 and GB200, making Korean semiconductor stocks a direct proxy for global AI infrastructure demand.

Although SK Hynix reported a record operating profit of 60.54 trillion Korean won ($41.25 billion), up 557% year-over-year, the result fell short of the 64 trillion won analyst consensus.

Leveraged Retail Bets Amplify Losses

The sell-off has been particularly painful for young Korean retail traders who shifted from cryptocurrency into AI and semiconductor shares in recent months. Korean crypto trading volumes have declined 28%, while the KOSPI had remained up 31% year-to-date before this week's crash.

The launch of single-stock leveraged exchange-traded funds for retail investors in May drew significant inflows. Assets under management in these products surpassed $50 billion in July. Following steep losses, senior policymakers have publicly apologized for approving the instruments and called for a renewed ban on retail access.

The turbulence underscores how semiconductor and AI equities are priced for near-flawless execution, exposing investors to significant downside risk if the sector's aggressive growth projections are not met. Korea's market structure — with two chipmakers dominating the index — magnifies this sensitivity, as any disappointment in HBM pricing or AI demand expectations transmits directly into national benchmark performance.

Credit Markets Signal Rising AI Risk

The semiconductor sell-off aligns with broader signs of strain across the AI trade, with uncertainty spilling from equities into credit markets.

Five-year credit default swaps on a basket of the five largest US hyperscalers — Amazon, Meta, Microsoft, Google, and Oracle — have climbed from 115 basis points to 162 basis points in recent months, reaching an all-time high. The market currently implies a 12% probability of default for these companies within a five-year horizon.

According to Sage Advisory, hyperscalers have more than doubled their collective dollar-denominated debt since September, surpassing $360 billion as free cash flow turns negative.

Oracle stands as the largest contributor to elevated credit risk following its aggressive AI infrastructure investments. While the company reports a substantial contract backlog, a significant portion is tied to OpenAI as a single customer — an entity that has faced cash flow difficulties and delayed its IPO.

Combined 2026 capital expenditure guidance from Alphabet, Microsoft, Amazon, and Meta is now tracking toward $725 billion to $730 billion, a figure that exceeds the combined annual revenue of the entire global semiconductor equipment industry and reflects an unprecedented concentration of infrastructure spending in a handful of firms. Alphabet posted its first cash burn on record in the second quarter at $5.9 billion, even as its cloud division grew 82%. Meta is scheduled to report its second-quarter results after US markets close, offering the next data point on whether hyperscaler spending commitments remain intact amid the widening market unease.