Kioxia (Kaischi) shares fell sharply 13.09% at the open on July 17, and were last at 53,980 yen. That is down more than 52% from the all-time high of 108,600 yen set in mid-June. The company’s market value has evaporated by at least $185 billion, slipping from Japan’s No. 1 to No. 4 by market cap. In mid-June, Kioxia shares jumped past Toyota Motor to become Japan’s highest market-cap company.
Kioxia is a major Japanese NAND flash memory manufacturer. After going public in 2024, its stock climbed steadily amid the AI boom that drove a surge in memory and data storage demand. In mid-June, it overtook Toyota Motor with an all-time high of 108,600 yen, and had previously been one of the best-performing components of the MSCI World Index.
On July 17, 2026, the stock sank 13.09% at the open and was last at 53,980 yen—down a cumulative more than 52% from the all-time high. The market value has evaporated by at least $185 billion, and its market-cap ranking has slid from first to fourth. This year, Japan’s market-cap leader has changed hands seven times already; the company currently sitting on top is Mitsubishi UFJ Financial Group.
In a Bloomberg interview, Yuugo Tsuboi, chief strategist at Daiwa Securities, cited the following three items as the main drivers of this leg of the selloff:
Silicon cycle: Memory chips have clear boom-and-bust cycles. Prices surge when supply is tight, but when capacity ramps up, they can easily collapse. Tsuboi said: “The semiconductor industry has always been very sensitive to the silicon cycle. We’ve already seen this pattern many times.”
Rise of Chinese competitors and capacity expansion by peers: Chinese memory manufacturers—including CXMT (ChangXin Memory Technologies)—have risen rapidly. Samsung Electronics and SK hynix have also announced capacity expansions one after another, and the market has started to worry that global memory price gains may slow and risks of oversupply could build up.
Fast-money exits: Tsuboi said: “Expectations that profit growth can keep accelerating have become increasingly hard to sustain. Fast-money investors may already have taken profits off the table.”
On Thursday, U.S. chip-sector indices plunged more than 4%. Concerns over TSMC’s AI investments outweighed its impressive earnings, and capital started rotating from AI-themed stocks to laggards, further adding to the backdrop of this selloff.
According to a Bloomberg report, market analysts’ consensus expects Kioxia to still have about 118% upside over the next year. It also expects the Japanese TOPIX Index to adjust its constituent stocks in October 2026, which is expected to bring in another wave of passive capital flows.
On the other hand, major shareholder Bain Capital has chosen to exit, and some investors interpret this as a sign that the semiconductor cycle and this rally in Kioxia may be peaking.
Japanese retail investors hold a relatively high proportion of leveraged positions in Kioxia. Based on market analysis, if selling pressure continues to accelerate, downside risk could be amplified by those leveraged positions. With two signals—an optimistic 118% upside view and the major shareholder’s exit—occurring at the same time, it reflects the market’s current split on this memory-market rally.
Based on opening data for July 17, 2026, Kioxia shares fell sharply 13.09% at the open and were last at 53,980 yen. That is down more than 52% from the all-time high of 108,600 yen set in mid-June, with market value evaporating by at least $185 billion and the market-cap ranking dropping from Japan’s No. 1 to No. 4.
According to remarks by Yuugo Tsuboi, chief strategist at Daiwa Securities, to Bloomberg, the three major causes are: the silicon cycle (memory’s inherent cyclical pattern), the rise of Chinese memory makers, and expanded capacity by Samsung/SK hynix that heightens concerns about oversupply, as well as fast-money investors getting out early and taking profits.
According to Bloomberg, analysts’ consensus expects Kioxia to have about 118% upside over the next year, and the TOPIX Index’s October constituent adjustment is also expected to bring in passive funds. However, major shareholder Bain Capital has already chosen to exit, so the two signals coexist at the same time.
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