Summary of Key Points
The largest shareholder of Japan's NAND flash memory giant, Kioxi, has changed: After its parent company, Toshiba, reduced its holdings, a company called BCPE (owned by Bain Capital and indirectly controlled by South Korea's SK Hynix through convertible bonds), has become the new largest shareholder. This didn't happen directly through SK Hynix' purchases; rather, it was a result of an indirect entry eight years ago via convertible bonds. Taking advantage of the soaring NAND market and the share reductions by both Bain Capital and Toshiba, BCPE rose to this position passively. This development has caused a stir in the global NAND industry—since SK Hynix is the world's second-largest NAND manufacturer, while Kioxi is third. The indirect control by SK Hynix over Kioxi could potentially change the competitive landscape of the industry and also impact the merger plans between Kioxi and Western Data. The situation will become even more complex once the voting rights restrictions expire in 2028.
I. Eight Years of Indirect Investment: How Did SK Hynix Quietly Become the Largest Shareholder?
This story begins in 2018 when Toshiba suffered significant losses in its nuclear power business and was forced to sell its most valuable memory division, which later became Kioxi. SK Hynix wanted to acquire it but feared anti-monopoly scrutiny due to concerns about a monopoly. Additionally, the transfer of semiconductor technology between Japan and South Korea was a sensitive issue, so they took an indirect approach: through BCPE (owned by Bain Capital), they invested $3.5 billion in convertible bonds that could be converted into shares, with voting rights restricted to no more than 15% until 2028.
Later, as demand for AI surged and NAND flash memory prices skyrocketed, Kioxi's stock price rose from 1,455 yen at its initial public offering to over 110,000 yen (with a market value briefly exceeding that of Toyota). While other companies under Bain Capital sold their shares to cash in, BCPE, controlled by SK Hynix, did not. Meanwhile, Toshiba continued to reduce its holdings in Kioxi. As a result, SK Hynix didn't buy any additional shares but inadvertently became the largest shareholder through the share reductions by others.
II. Why Is the Control of the Third-Largest Player by the Second Largest So Sensational?
There are only a few players in the global NAND market: In the first quarter of 2026, Samsung held 29%, SK Hynix 18%, and Kioxi 14%. Now, with SK Hynix indirectly controlling Kioxi, their combined market share is close to 40%, nearly matching Samsung's. Moreover, they are direct competitors, competing in areas from mobile storage to data center SSDs.
The technology aspect is even more critical: Kioxi had just started mass-producing 332-layer NAND, while SK Hynix is working on 375-layer NAND, and Samsung has already reached beyond 400 layers. If SK Hynix gains control over Kioxi's decision-making, core secrets such as technology routes, production capacity planning, and customer lists could be exposed. Kioxi itself acknowledges that this could lead to conflicts of interest. However, in the short term, SK Hynix is hesitant to convert its convertible bonds into shares and exercise its voting rights due to the need to pass anti-monopoly reviews in multiple countries, including South Korea, Japan, the United States, and China. Given the current tense global semiconductor geopolitics, Japan is unlikely to allow a South Korean company to directly control what it considers the "father of NAND" technology (Kioxi, which inherited Toshiba's NAND capabilities).
III. The Reasons Behind the Failed Merger: Why Does SK Hynix Oppose the Kioxi-Western Data Merger?
Kioxi and Western Data were once a good partnership, sharing factory capacity and having deep technical ties. Western Data wanted to merge in 2021; together, they would have held a 31% market share, surpassing Samsung. However, the merger fell through due to SK Hynix' opposition in 2023. Now that SK Hynix is the largest shareholder, the merger has become even more difficult.
SK Hynix opposes the merger because it would create a competitor larger than itself, potentially threatening its market position. The U.S. and Japanese governments have pressured SK Hynix, but South Korea is not convinced by these arguments. Behind this is geopolitics: Japan wants to protect its domestic semiconductor industry, the U.S. aims to consolidate allies against China, and South Korea seeks to maintain its dominance in the storage sector. Additionally, China's Yangtze Memory Technologies has also made rapid progress (with its market share rising from 8% to 13%), complicating the geopolitical dynamics among these countries.
IV. The Critical Year: What Will Happen After 2028?
2028 marks a pivotal year as SK Hynix' voting rights restrictions will expire. The outcome depends on three factors:
1. Market Trends: If AI demand persists and NAND prices remain high, SK Hynix may continue to be a passive shareholder, earning dividends. If the market declines and integration becomes necessary, SK Hynix could push for a merger with Kioxi (to compete with Samsung) or facilitate a merger between Kioxi and Western Data (to combine production capacities from Japan and the U.S.).
2. Anti-Monopoly Regulations: Whether governments will relax regulations to allow SK Hynix to directly control Kioxi is uncertain; current trends suggest this is unlikely, but future policy changes are unpredictable.
3. Toshiba's Actions: Toshiba still holds 14.12% of Kioxi's shares, and if it further reduces its holdings, SK Hynix' influence will increase.
In summary, the global NAND market landscape could be reshaped after 2028: whether Samsung becomes dominant, or a combination of SK Hynix and Kioxi challenges Samsung, or new mergers occur, all depends on how these factors unfold.
This incident is a microcosm of the global semiconductor industry's geopolitical and competitive dynamics—where technology, capital, and politics intersect. Every change in ownership could affect the entire industry's trajectory. For consumers, this might also impact the prices and pace of technological advancements in storage products.