Kioxia loses half its value in a month as chip stocks crater globally

Kioxia Holdings, the Japanese memory chipmaker that briefly became the country's most valuable listed company in June, saw its shares plunge 16% on Thursday, extending a punishing decline that has erased roughly half of its market capitalization in less than a month.

The stock closed at ¥52,110 on Friday after falling from a 52-week high of ¥112,700 set on June 22, a collapse that has wiped approximately ¥29.5 trillion ($182 billion) in market value. Kioxia, which overtook Toyota to become Japan's largest company by market cap in mid-June with a valuation exceeding ¥50 trillion, has now dropped to fourth place among the country's most valuable firms.kucoin+2

A Broader Semiconductor Rout

The selloff is not confined to Kioxia. Thursday's session saw the Nikkei 225 close 2,694 points lower at 64,141 — its fifth-largest single-day drop on record. The Philadelphia Semiconductor Index PHLX Semiconductor Sector ↘ 1.19% tumbled 4.3% in a second straight day of losses, even as Taiwan Semiconductor Manufacturing Company ↘ 1.20% reported earnings growth of 77% that failed to satisfy investors who had priced in continued AI-driven gains.youtube+1

In Japan, other chip-related stocks including Tokyo Electron, Ibiden, and Sumco fell between 8% and 10%. South Korea's Kospi plunged over 6% earlier in the week, with SK Hynix and Samsung Electronics sliding between 8% and 11%.xtb+1

Warning Signs Were Mounting

Analysts point to several factors behind Kioxia's dramatic reversal. The company's stock had surged more than 800% in 2026 before the correction began, driven by insatiable AI-related demand for NAND flash memory. But Bain Capital's complete exit from its stake — confirmed on July 8 by Managing Partner David Gross — signaled that one of the company's earliest backers saw the cycle peaking. Bain had held roughly 44% of Kioxia as recently as December 2025 and methodically wound down its position over six months, logging an estimated $15 billion in profit.investing+3

Meanwhile, China's Yangtze Memory Technologies is building three new factories that would more than double its capacity by end of 2027, raising concerns about a potential NAND oversupply. YMTC is targeting 15% global NAND shipment share in 2026, approaching the scale of SK Hynix.eetimes+2

The memory chip sector's inherent boom-bust cyclicality leaves investors questioning whether the AI-driven upcycle has peaked — or whether the selloff is simply the kind of violent correction that speculative rallies inevitably produce.