⚠ The Partner Is Building the Same ChipsHigh threat

Kioxia Holdings (285A) — threat to the moat

Sandisk gets Kioxia's technology at Kioxia's cost and competes with it at thirteen percent share against fourteen -- there is no engineering answer to that.

Kioxia's manufacturing partner is a competitor with an unusual advantage: it gets Kioxia's technology at Kioxia's cost.

Sandisk's purchases from Kioxia (¥bn)¥170.5bn, 15.8%Year to Mar 2024¥198.6bn, 11.6%Year to Mar 2025Kioxia Annual Securities Report FY2024 and FY2025; below the 10% threshold in the year to March 2026
The partner buys less from Kioxia as a share each year while building the same chips.

Sandisk's own prospectus states that substantially all of its flash memory comes from the joint ventures with Kioxia, and that the two co-develop the process technology and memory design and jointly own the result1. Sandisk then competes with Kioxia for the same customers, at roughly the same share of the market — 13% against 14% in the first quarter of 20262.

Most companies in this collection have a rival they must out-engineer. Kioxia has one it cannot out-engineer by construction, because the engineering is jointly owned. What separates them is controllers, firmware, channel and brand — everything except the part that costs ten billion dollars to build.

The counterweight is symmetry: Sandisk is equally unable to out-manufacture Kioxia, and the arrangement gives both a cost position neither could fund alone. It also makes Sandisk a substantial customer — it was 15.8% of Kioxia's revenue in the year to March 2024 and 11.6% the year after3.

The falsifier would be Sandisk sourcing meaningfully from outside the ventures. Its filing notes it buys from other manufacturers from time to time4; if that stops being occasional, the structure is unwinding.

References
  1. ReportedSandisk and Kioxia co-develop the process technology and memory design and jointly own the result.
    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 ↗
  2. Third-party estimateSandisk held about 13% of NAND revenue in Q1 2026 against Kioxia's 14%.
    Counterpoint Research — global NAND memory market share. The NAND market reached a record US$46 billion in the first quarter of 2026, growing about 90% sequentially and roughly 3.5 times against the first quarter of 2025. Share by revenue: Samsung 29%, SK hynix 18%, Kioxia 14%, Micron 13%, Sandisk 13% and YMTC 13% — YMTC having risen from about 8% a year earlier. — Q1 2026 · publ. 2026 · source ↗
  3. ReportedSandisk was 15.8% of Kioxia's revenue in the year to March 2024 and 11.6% the year after.
    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 ↗
  4. ReportedSandisk's filing notes it also purchases flash memory from other manufacturers from time to time.
    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