Marvell Technology (MRVL) shares plunged 5.09% during intraday trading on Monday, as the global semiconductor sector faced relentless selling pressure driven by escalating turmoil in Korean markets and mounting concerns over AI capital expenditure sustainability.

The selloff was exacerbated by extreme volatility in South Korea, where the KOSPI index tumbled over 5% and triggered circuit breakers, with Samsung Electronics and SK Hynix each plunging more than 8%. The ongoing deleveraging process in Korean markets spilled over into broader chip sentiment worldwide, dragging down major semiconductor peers including Micron Technology, Intel, and Advanced Micro Devices. The Philadelphia Semiconductor Index had already fallen over 25% from its June highs in recent weeks, reflecting growing unease over crowded momentum trades and the durability of AI-driven spending.

Marvell's decline came despite the company's announcement of its participation in the FMS 2026 conference, where it plans to showcase its AI memory and storage infrastructure portfolio. However, the broader macroeconomic and sectoral headwinds overshadowed any company-specific developments, as traders continued to unwind positions across the semiconductor space.