Kioxia's 3-for-1 Split: How to Read Its Price History

Kioxia Holdings (285A, Tokyo Stock Exchange Prime) split each common share into three. The record date was September 30, 2026 and the split took effect on October 1. Every share became three, and the price per share fell to about a third. Nothing else about the company changed. Sites differ because some rewrite the old prices to match the new share count (“adjusted”) and some leave them as they traded (“unadjusted”). To compare a pre-split price with a post-split one, divide the pre-split price by 3.

Prices below are Tokyo Stock Exchange closing prices in yen. Dollar figures use the yen-dollar rate published by the Bank of Korea (ECOS) for the day named.

What exactly did Kioxia announce?

The board approved the split on July 31, 2026. Kioxia’s notice gives the terms:

Item	Detail
Ratio	3 shares for each 1 share held
Record date	Wednesday, September 30, 2026
Effective date	Thursday, October 1, 2026
Shares outstanding	548,015,088 before; 1,644,045,264 after (June 30 count)
Authorized shares	2,070,000,000 raised to 6,210,000,000

The company said the aim was to lower the amount needed per trading unit and widen its investor base. It noted the Tokyo Stock Exchange’s request that an investment unit cost less than 500,000 yen, and said it would keep considering further reductions. Japanese domestic stocks trade in units of 100 shares, according to Japan Exchange Group.

The same day, Kioxia set up a facility to acquire up to 30 million of its own shares, for up to 800 billion yen. The notice said the cap would become 90 million shares after the split. By August 10 it had finished: 16,133,500 shares for 799,997,689,000 yen, all before the split. Those 16,133,500 shares equal 48,400,500 post-split shares.

Which day did the price change?

The record date was Wednesday, September 30, but the price fell to a third one trading day earlier. In Tokyo, trades from the business day before a record date onward no longer carry the right attached to it, as Japan Exchange Group describes for dividends. Kioxia shares began trading on the post-split basis on Tuesday, September 29, as MONEY PLUS (Money Forward) and Business Insider Japan reported. The Osaka Exchange adjusted Kioxia stock options on the same day, dividing strike prices by 3 and multiplying positions by 3.

So the last close at the old, pre-split level was Monday, September 28. Every close from September 29 on is already on the new basis.

Adjusted vs unadjusted: what is the difference?

An unadjusted history shows each price exactly as it traded that day. It has a cliff at September 29, where the price drops by about two-thirds for no economic reason.

An adjusted history divides every close before September 29 by 3. The cliff disappears, and the line shows what one of today’s shares was worth on each earlier day. The prices quoted in this article are adjusted. To get back the price as it traded:

• unadjusted pre-split price = adjusted price × 3
• adjusted pre-split price = unadjusted price ÷ 3

This is also why adjusted charts show odd fractions. A close of 108,700 yen divided by 3 is 36,233.33 yen, a price that never traded.

A worked example: September 28 and October 20

	Sep 28 (pre-split)	Oct 20 (post-split)
Close as traded (unadjusted)	53,340 yen	13,140 yen
Close, adjusted for the split	17,780 yen	13,140 yen
100 shares at the close	5,334,000 yen	1,314,000 yen
Yen per dollar (ECOS)	157.595	158.55
100 shares in dollars	about $33,846	about $8,288

Post-split prices are the same in both versions. Only the earlier one changes.

Compare like with like, and the stock moved from 17,780 yen to 13,140 yen: a fall of 26.1% from September 28 to October 20. Mix the two versions, 53,340 yen against 13,140 yen, and you get a “fall” of 75.4%. That figure is wrong. Most of it is the split.

In dollars, one share closed at 13,140 yen on October 20. At ECOS’s rate of 158.55 yen per dollar that day, that is about $82.88 per share. One 100-share unit cost about 1.31 million yen, against about 5.33 million yen at the last pre-split close. That is still above the 500,000-yen level the exchange asks for.

Why do sites show such different 52-week ranges?

Three things change the numbers.

Adjusted or not. A page that keeps unadjusted history keeps the old, higher prices in its range. In the closes used here, the highest close was 108,700 yen as traded on June 22, 2026. Adjusted, that is 36,233.33 yen. A range built from raw history would show a high more than eight times the October 20 close. Adjusted, the October 20 close is 63.7% below the high. Mixed, it looks 87.9% below.

Closes or intraday prices. Many quote pages build their range from intraday highs and lows. Those reach further than closing prices, so the range is wider than one built from closes.

The window. The figures here cover December 1, 2025 to October 20, 2026, just under 11 months, not a full 52 weeks. A true 52-week window would reach back to October 2025.

Within that span, the adjusted closes ranged as follows:

	Date	Adjusted close	As traded
Highest close	June 22, 2026	36,233.33 yen	108,700 yen
Lowest close	December 16, 2025	2,896 yen	8,688 yen
Latest	October 20, 2026	13,140 yen	13,140 yen

When two sites disagree, check whether both are adjusted and both use closes. Usually that explains the gap.

What about the IPO price?

Kioxia set its offering price at 1,455 yen per share on December 9, 2024, and completed its listing on the Tokyo Stock Exchange Prime Market on December 18, 2024. That price was set on the old share count. On today’s basis it is 1,455 ÷ 3 = 485 yen. The October 20 close of 13,140 yen is about 27 times that adjusted figure. Against the unadjusted 1,455 yen it would look like 9 times, which understates the move.

How do I adjust per-share figures in older releases?

Earnings per share, dividends per share and share counts in documents dated before October 1 use the old share count. Divide per-share amounts by 3. Multiply share counts by 3.

Kioxia says so itself. Its results for the three months ended June 30, 2026, released July 31, say the figures “do not factor in this stock split.” Basic earnings per share for that quarter were 1,539.91 yen. Per post-split share, that is 1,539.91 ÷ 3 = 513.30 yen. Use the adjusted figure when you set it against a post-split price.

The same release shows a dividend of 0.00 yen for the fiscal year ended March 2026, and a forecast of 0.00 yen for the end of the second quarter. A zero stays zero after the split.

Kioxia has scheduled its next results, for the quarter to September 30, for October 30, 2026. Check the notes in each release for which share count it uses.

Where can I see Kioxia next to its peers?

The Japan map shows Kioxia’s daily move beside other Japanese chip stocks. For how a US-based investor can reach Tokyo-listed shares, see Asia chip stocks from a US account. A split changes the size of a share and the look of its chart. It does not change what the whole company is worth or what each holder owns in total.