The Customer Who Owns Half the FactoriesNarrow moat

Kioxia Holdings (285A) — moat facet

Supplier, co-owner, customer and competitor at once -- there is no clean word for what Sandisk is, and that is the point.

The second name in Kioxia's customer table is its manufacturing partner.

What Sandisk is to KioxiaCo-ownerSeven of nine plants, equal controlPartnerJointly owned process technologyCustomer15.8%, then 11.6%, then below 10%Competitor13% of NAND against Kioxia's 14%Sales to Sandisk through the joint ventures sit inside the 'Other' application line.
There is no clean word for this relationship, and that is the point.

Sandisk accounted for ¥170.5 billion of Kioxia's revenue in the year to March 2024 (15.8%) and ¥198.6 billion the following year (11.6%), before falling below the 10% disclosure threshold in the year to March 20261. Kioxia's own segment note explains part of the mechanism: the "Other" application category includes sales to the Sandisk group recorded through the three manufacturing joint ventures2.

So the flows run in every direction at once. The two companies jointly own the fabs and the process technology3. Kioxia operates the plants. Sandisk takes its share of the output — and buys more besides — then sells finished drives against Kioxia's finished drives.

There is no clean way to describe this relationship, and that is the point. A customer at 15.8% of revenue is a dependency; a co-owner of your factories is a partner; a producer at 13% share is a competitor. Sandisk is all three, and has been for two decades.

The reason it works is that neither party has an alternative that costs less than the arrangement.

The number to watch is whether the Sandisk line reappears above 10%. Its disappearance in the most recent year reflects Kioxia's revenue growing 37%, not the relationship shrinking.

Moat trajectory: Holding steady

Sandisk went from 15.8% to 11.6% to below 10% of revenue, entirely because Kioxia's total grew. The structural relationship was extended to 2034 in the same period.

The number that tests this moat
Reported
Sandisk revenue, three years
¥170.5bn → ¥198.6bn → below 10%

15.8% then 11.6% then under the disclosure threshold, and Kioxia's segment note records sales to Sandisk through the three manufacturing joint ventures inside the 'Other' category. Supplier, co-owner, customer and competitor at once. Watch whether the line reappears above 10%.

Source: Kioxia Holdings, Annual Securities Report for the year to 31 March 2026 ↗
References
  1. ReportedSandisk was ¥170.5bn (15.8%) and ¥198.6bn (11.6%) of revenue before falling below the 10% threshold in the year to March 2026.
    Kioxia Holdings Corporation, Annual Securities Report for the year from 1 April 2024 to 31 March 2025 (7th Period) — revenue ¥1,706,460M against ¥1,076,584M; revenue by application SSD & Storage ¥991,147M against ¥516,361M, Smart Devices ¥501,142M against ¥374,293M, Other ¥214,171M against ¥185,930M. Major customers, with the ratio to total sales: Apple group ¥225.3bn (20.9%) in the year to March 2024 and ¥300.5bn (17.6%) in the year to March 2025; Sandisk group ¥170.5bn (15.8%) and ¥198.6bn (11.6%); Dell group ¥94.0bn (8.7%) and ¥171.2bn (10.0%). Revenue in the United States ¥758,666M against ¥393,909M and in China ¥323,357M against ¥217,870M; non-current assets in Japan ¥1,714,351M against ¥1,737,806M. Total equity ¥737.7bn against ¥449.8bn. — year to 31 March 2025 · publ. 2025-06 · source ↗
  2. ReportedThe 'Other' application category includes sales to the Sandisk group recorded through the three manufacturing joint ventures.
    Kioxia Holdings Corporation, Annual Securities Report for the year from 1 April 2025 to 31 March 2026 (8th Period) — revenue ¥2,337,628M against ¥1,706,460M, gross profit ¥1,012,904M, operating profit ¥869,013M, profit for the year ¥554,490M; research and development cost ¥141,052M against ¥132,798M; purchases of property, plant and equipment ¥281,062M against ¥223,847M; operating cash flow ¥616,540M; proceeds from government grants ¥56,396M against ¥43,748M, from an approved ceiling of ¥150.0bn for flash production at the Yokkaichi and Kitakami plants with about ¥31.8bn not yet received. Revenue by application: SSD & Storage ¥1,362,638M, Smart Devices ¥759,978M, Other ¥215,012M — 'Other' including retail products and sales to the Sandisk group recorded through the three manufacturing joint ventures. Revenue by geography: Japan ¥263,252M, North America and Europe ¥1,217,643M, Asia ¥856,733M, with the United States ¥1,098,832M, China ¥381,857M and Taiwan ¥300,932M. Non-current assets: Japan ¥1,658,950M, North America and Europe ¥1,986M, Asia ¥6,298M. Major customers: Apple group ¥476,014M (20.4%), with the Sandisk and Dell groups omitted for the year as each fell below 10% of sales. Flash Partners Ltd., Flash Alliance Ltd. and Flash Forward LLC are accounted for as joint operations with 50.1% of the voting rights and equal decision-making rights shared with Sandisk. Net interest-bearing debt ¥552,085M against equity of ¥1,398,929M — a net debt-to-equity ratio of 0.39 times, from ¥931,035M against ¥737,565M and 1.26 times a year earlier; USD-denominated senior notes at 6.25% (2030) and 6.625% (2033); goodwill of ¥395,585M from the 1 June 2018 acquisition of the former Toshiba Memory Corporation. Bain Capital funds indirectly hold 21.87% and Toshiba Corporation 17.59% of outstanding common shares, both having sold substantial holdings during the year. Risk factors state that the Yokkaichi Plant is located in an area with a high risk of earthquakes and floods and the Kitakami Plant in an area severely damaged by the 2011 Tohoku Earthquake, and name US-China trade frictions and US tariff policy among factors that may materially affect the business. The company does not provide plans or progress reports for the overall fiscal year. — year to 31 March 2026 · publ. 2026-06 · source ↗
  3. ReportedThe two companies jointly own the fabs and the process technology.
    Sandisk Corporation, Form 424B4 prospectus (SEC, CIK 2023554) — Sandisk and Kioxia operate three business ventures, Flash Partners Ltd., Flash Alliance Ltd. and Flash Forward Ltd. (collectively 'Flash Ventures'), across seven flash-based manufacturing facilities in Japan, six in Yokkaichi and one in Kitakami, with an eighth beginning operations in calendar year 2025. 'We co-develop flash technologies (including process technology and memory design) with Kioxia for Flash Ventures' use. We and Kioxia jointly own these co-developed flash technologies.' 'Substantially all of our flash-based memory is obtained from our joint ventures with Kioxia... While substantially all of our flash memory supply utilized for our products is purchased from these ventures, from time to time, we also purchase flash memory from other flash manufacturers.' Sandisk names Kioxia, Micron, Samsung, SK Hynix and YMTC among its competitors, and completed its separation from Western Digital in February 2025. — FY2025 · publ. 2025-05 · source ↗
Sources
Generated September 23, 2026