The setup
Kioxia is the former Toshiba memory division — today the world's second-largest maker of NAND flash and SSDs, and since its Tokyo listing one of the purest large-cap ways to own the NAND cycle directly. Unlike a controller house or a module packager, Kioxia is the fab: it makes the wafers, so when NAND tightens it captures the price move at the source rather than as a pass-through. The fiscal year ended (Kioxia labels it FY2025) is the first full year in which that leverage broke decisively the company's way.
The backdrop is the cleanest memory upcycle since 2017–18: AI datacenter buildout is vacuuming up high-density NAND and SSD capacity, the leading suppliers have tilted output toward AI and enterprise parts, and supply has tightened across the board as a second-order effect. The release — Q4 plus full-year FY2025, paired with current-quarter guidance — is what that tape looks like when it lands on a wafer maker with no intermediary skimming the spread.
The numbers
Fiscal Q4 (the quarter ended ) set single-quarter records across the board. Revenue of ¥1,002.9 billion (~$6.3B) cleared the ¥1 trillion mark for the first time, up 188.9% year-on-year. Operating profit reached ¥596.8 billion (~$3.8B), a more-than-15-fold increase, and net profit came in at ¥407.7 billion (~$2.6B), up close to 20-fold. The driver was disclosed plainly: U.S. dollar-denominated NAND selling prices roughly doubled sequentially even as shipment volumes fell about 10% quarter-on-quarter — price, not units, carried the quarter, which is the signature of a genuine shortage rather than a volume ramp.
For the full FY2025 year, revenue crossed ¥2 trillion for the first time at ¥2,337.6 billion (~$14.7B), up 37%; operating profit was ¥870.4 billion, up 92.7%; and net profit attributable to shareholders was ¥554.5 billion, up 130.6% — all three core metrics at record highs. The balance sheet repaired alongside the P&L: operating cash flow rose to ¥616.5 billion, cash and equivalents improved to ¥470.7 billion, and the equity ratio climbed from 25.3% to 37.9% as shareholder equity reached roughly ¥1.4 trillion, aided by a capital-restructuring program (USD bond issuance, long-term-loan repayment, preferred-share redemption).
The line that reframes everything is the guide. For the current quarter (April–), Kioxia forecasts revenue of ¥1.75 trillion (~$11B, +~75% QoQ), operating profit of ¥1.298 trillion (~$8.2B), and net profit of ¥869 billion (~$5.5B) — roughly 46x year-on-year. Consensus had pencilled current-quarter net profit at only about ¥405.6 billion, so the guide is more than a double over the Street. And the framing that matters: that single guided quarter (¥869B net) is larger than the entire ¥554.5B of net profit Kioxia just booked for all of FY2025. That is a cycle inflecting violently, not a steady compounder grinding higher.
The rest of this dive is for paid subscribers.
The headline numbers are above. The 6 sections below carry the mechanism, the peer read, the valuation work, and the dated tests that decide it.
- What's actually driving it
- How peers read this
- Valuation reality check
- What we'd watch from here
- Listed-market read-through
- Bottom line
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