The Nasdaq's June 23 Plunge: Why Micron, SanDisk and Kioxia Fell Hardest
On June 23, 2026, the Nasdaq fell 2.2% as memory chip stocks led the AI selloff — Micron −11%, SanDisk −12.6%, and Korea's market hit a circuit breaker. A comparison of Micron, SanDisk and Kioxia, and why they fell even as NAND sells out. Analysis, not investment advice.
TL;DR — On June 23, 2026, the Nasdaq fell 2.2% as the memory-chip stocks that led the AI rally led the fall: Micron dropped about 11% and SanDisk about 12.6%, while Korea's market hit a circuit breaker. The strange part — demand has never been better. This was a crowded-trade selloff, not a broken business.
The same stocks that powered 2026's record rally just delivered its sharpest reversal. Here's what happened to the memory names — Micron, SanDisk, Kioxia and the Korean giants — and why they all fell together even as their order books overflow. (Information, not advice.)
What happened
The Nasdaq Composite fell 2.2% and the S&P 500 1.44% on Tuesday, June 23, dragged down by a 7.9% drop in the semiconductor index — the very group that had been "the leader of a record-setting rally," per Reuters/MarketScreener. Memory got hit hardest.
The memory trio (and the Koreans), compared
| Memory/storage stock | Listing | What it makes | June 23, 2026 |
|---|---|---|---|
| Micron | MU · Nasdaq | DRAM, NAND, HBM | −11% (~$1,075; −13% intraday) |
| SanDisk | SNDK · Nasdaq | NAND flash, SSDs | −12.6% (~$2,007) |
| Kioxia | 285A · Tokyo | NAND flash (pure-play) | swept up in the global memory selloff* |
| SK Hynix | 000660 · Seoul | DRAM, HBM, NAND | −12%+ (KOSPI tripped a circuit breaker) |
| Samsung | 005930 · Seoul | DRAM, NAND, HBM | down double digits |
Kioxia is Tokyo-listed and wasn't separately quantified in US coverage — but it's now Japan's most valuable company, and its entire 2026 NAND output is already sold out, with dollar NAND prices up more than 100% in a quarter.
The split worth noting: Micron plays in everything — DRAM, NAND flash, and the HBM that feeds AI accelerators — while SanDisk (spun out of Western Digital in early 2025) and Kioxia (the former Toshiba Memory) are the NAND/flash specialists. On June 23, the market sold them all the same way.
Why they fell — when demand is booming
This is the puzzle. NAND is in shortage: Kioxia's entire 2026 output is sold out and dollar prices have more than doubled in a quarter. Yet the stocks cratered. Three reasons converged, per Yahoo Finance:
- AI-spending fatigue — scrutiny of "AI firms' escalating capital expenditures" and debt-funded data centers.
- A hawkish Fed — traders braced for higher rates, which punish richly-valued growth stocks.
- A crowding unwind — after a run that made Micron and SanDisk among the S&P 500's best performers, the trade was simply too crowded.
"Some of the news lately about AI raises questions about all the spending that's being done and the capex and ramping of the capacity for semiconductors," said Thomas Martin, senior portfolio manager at Globalt.
The next test
The timing is brutal: Micron reports earnings on June 24 — the day after the crash. With the whole memory complex priced for perfection, its results and guidance are now the market's verdict on whether the AI-memory boom is still accelerating or finally cresting.
FAQ
What caused the Nasdaq selloff on June 23, 2026?
A semiconductor-led drop: the chip index fell 7.9% and the Nasdaq 2.2%, as investors worried about AI firms' heavy capital spending and a more hawkish Federal Reserve, unwinding a crowded AI trade.
How far did Micron, SanDisk and Kioxia fall?
Micron dropped about 11% (to ~$1,075, with intraday losses near 13%) and SanDisk about 12.6% (to ~$2,007). Kioxia, Tokyo-listed, was swept up in the same global memory selloff but wasn't separately quantified in US coverage.
What's the difference between these companies?
Micron makes DRAM, NAND flash and HBM; SanDisk (spun from Western Digital in 2025) and Kioxia (formerly Toshiba Memory) are NAND/flash specialists; Samsung and SK Hynix make DRAM, NAND and HBM.
If demand is so strong, why did the stocks fall?
Because the selloff was about valuation and positioning, not demand. NAND is sold out and prices are surging — but the stocks had become crowded, expensive AI bets vulnerable to any wobble in sentiment or rate expectations.
What should I watch next?
Micron's June 24 earnings — the first hard read on whether AI-memory demand is still accelerating. (This is information, not investment advice.)
Sources: Yahoo Finance, TheStreet, Reuters via MarketScreener, CNN; Kioxia capacity via Digitimes.
Image: bfishadow on Flickr, CC BY 2.0, via Wikimedia Commons.
General market information, not investment advice. Figures are as of June 23, 2026 and move fast.
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