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How much the Nikkei 225 moves overnight: 18 hours, measured
- Across 69 Tokyo trading days, the median absolute change was 0.68% in the daytime window (9:00 → 15:00) and 1.08% in the overnight window (15:00 → 9:00 the next day).
- Split into equal six-hour blocks, the daytime window was 0.68% and the three overnight blocks were 0.33%, 0.77% and 0.48%.
- The figures are Hyperliquid perpetual-futures reference values. They are not the Nikkei 225 itself.
Section highlights (8)
- What was measured is a perpetual-futures reference value. No candles were missing over the period.
- The daytime observation window is the 6 hours from 9:00 to 15:00; the overnight window is the 18 hours from 15:00 to 9:00 the next day.
- The statistics cover 69 Tokyo trading days. The 8 days that touch a holiday are in a separate table.
- Under the weekday times in the specification, one hour of the 18-hour overnight window (6:00 to 7:00) is an internal-pricing hour. Holidays are handled in a separate table.
- The 18-hour overnight window had a median of 1.08%; the six-hour daytime window, 0.68%. The lengths differ by a factor of three.
- In six-hour blocks: 0.77% for 21:00–3:00, 0.68% for the daytime window, 0.48% for 3:00–9:00 and 0.33% for 15:00–21:00.
- The share of the range was 83.17% for the 18-hour overnight window; among six-hour blocks the daytime window's 59.45% was the largest.
- These are perpetual-futures reference prices. The original statistics and the update cover separate periods.
Contents
- 9:00 → 15:00 (daytime observation window)0.68%
- 15:00 → 21:000.33%
- 21:00 → 3:00 next day0.77%
- 3:00 → 9:00 next day0.48%
- 15:00 → 9:00 next day (overnight window, 18 hours)1.08%
The top four bars are equal six-hour blocks. The bottom bar is the 18-hour overnight window, three times as long. Reference values calculated from hourly candle closes of the perpetual future xyz:JP225.
The cash session at the Tokyo Stock Exchange runs from 9:00 to 11:30 and from 12:30 to 15:30 JST.
Source: Japan Exchange Group, Trading Hours for Domestic Stocks. Retrieved 16 October 2026.
This article uses hourly candles. It cuts at 09:00 and 15:00 JST, using the close of the candle that completes at each time.
The last hourly candle to complete before the 15:30 close is the one that completes at 15:00. The 30 minutes from 15:00 to 15:30 fall in the overnight window.
The span between those cuts is the daytime observation window (6 hours); the rest is the overnight window (18 hours). These are aggregation windows aligned to candle closes, not the trading session itself.
Hourly perpetual-futures candles provide a reference-price series for the hours outside the daytime observation window.
The original sample covers April to August 2026. Of the 77 days that start on a Monday through a Thursday, 8 touch a Tokyo Stock Exchange holiday and are listed separately. The statistics cover the remaining 69 trading days.
What was measured, and how
The data source and what it covers
The subject is the hourly candles of the Hyperliquid perpetual future xyz:JP225. They were retrieved on 25 August 2026.
This price is not the Nikkei 225 itself. It is a reference value of a contract that references it. The same distinction is set out in what a perpetual future is.
How the solid and dashed lines are drawn is covered in How to read a StockTicker24 card.
The original sample contains 3,325 hourly candles, with 0 missing.
What was measured is a perpetual-futures reference value. No candles were missing over the period.
The two windows
The day was split into two windows. Each endpoint uses the close of the hourly candle completing at that time. All times in this table are Japan Standard Time (JST).
| Window | Definition | Length |
|---|---|---|
| Daytime observation window | 09:00 → 15:00 JST | 6 hours |
| Overnight window | 15:00 → 09:00 JST on the next day | 18 hours |
The candle completing at 09:00 starts at 08:00; the candle completing at 15:00 starts at 14:00. A Friday night runs into the weekend, so the overnight window counts only days that start on a Monday through a Thursday.
The daytime observation window is the 6 hours from 9:00 to 15:00; the overnight window is the 18 hours from 15:00 to 9:00 the next day.
How Tokyo Stock Exchange holidays are handled
Perpetual futures also move on Tokyo Stock Exchange holidays. On a holiday, however, the hours from 9:00 to 15:00 do not coincide with a cash session.
The statistics therefore count only days on which both the start date and the next day are Tokyo trading days: 69 of the 77 Monday-to-Thursday days.
The 8 days on which the start date or the next day is a holiday are left out of the statistics and listed below. Holidays follow the Japan Exchange Group market-holiday calendar. For each of these 8 rows, the start date or the following day is a national holiday.
Calendar retrieved 16 October 2026.
Open the table: Days that touch a Tokyo Stock Exchange holiday (8 rows)
| Start date (JST) | Day | Holiday | Change, 9:00 → 15:00 | Change, 15:00 → 9:00 next day |
|---|---|---|---|---|
| 2026-04-28 | Tue | Next day | -1.26% | -0.96% |
| 2026-04-29 | Wed | Start date | +0.41% | -0.40% |
| 2026-05-04 | Mon | Start date and next day | +0.98% | -1.32% |
| 2026-05-05 | Tue | Start date and next day | +0.41% | +2.54% |
| 2026-05-06 | Wed | Start date | +0.13% | +1.39% |
| 2026-07-20 | Mon | Start date | -0.09% | +0.08% |
| 2026-08-10 | Mon | Next day | +0.96% | -0.68% |
| 2026-08-11 | Tue | Start date | +0.77% | +0.43% |
The statistics cover 69 Tokyo trading days. The 8 days that touch a holiday are in a separate table.
Where the values come from — external and internal pricing
This contract has two kinds of reference price: an external price and an internal price. The terms are the same as in the contract section of the Nikkei 225 symbol page.
The external price is one the issuer derives from values in outside markets. The specification describes it as combining index values during the cash session with futures quotes.
The internal price is one derived from the contract's own order-book quotes, for hours when no outside value is available.
The specification lists three items as internal-pricing hours for the Nikkei 225 contract: weekdays from 6:00 to 7:00 Japan time, Saturday 6:00 to Monday 7:00, and holidays. Sources: trade[XYZ], Specification Index, Japan and Holiday Closures. Retrieved 16 October 2026.
The holidays item gives no times and points to a separate table of holiday closures. That table has a column of Japanese equity market holidays and a column of holiday trading hours for futures. It does not state which column applies to the Nikkei 225 contract.
Applying the weekday times, the 18-hour overnight window contains one hour of internal pricing (6:00 to 7:00). The other 17 hours are external-pricing hours. The dates in the separate table are not applied in this calculation.
The 69 days in the statistics include none of the dates in the Japanese equity column. 25 May, which is in the futures column, is one of the 69 start dates.
The hourly candles in this article are traded prices of the perpetual future. They are not the reference price itself, and they do not record whether each candle fell under external or internal pricing.
Under the weekday times in the specification, one hour of the 18-hour overnight window (6:00 to 7:00) is an internal-pricing hour. Holidays are handled in a separate table.
The result — an 18-hour window, and four six-hour blocks
The 18-hour and six-hour figures side by side
Open the table: The 18-hour and six-hour windows side by side (5 rows)
| Item | Daytime observation window (6 hours, N=69) | Overnight window (18 hours, N=69) |
|---|---|---|
| Median absolute change | 0.68% | 1.08% |
| Days beyond ±0.5% | 66.67% (46/69) | 78.26% (54/69) |
| Days beyond ±1% | 42.03% (29/69) | 53.62% (37/69) |
| Largest rise | +2.89% (2026-06-11) | +3.83% (night of 2026-07-30) |
| Largest fall | -3.35% (2026-06-23) | -2.30% (night of 2026-06-10) |
The overnight absolute change exceeded the daytime window on the same day on 42 of the 69 days, or 60.87%.
This table sets two windows of different lengths side by side. The overnight window is three times as long as the daytime observation window.
"Night of 2026-07-30" in the table is the value of the overnight window that starts on 30 July. The window runs from the close of the candle completing at 15:00 JST to the close of the candle completing at 9:00 JST on the next day.
The 18-hour overnight window had a median of 1.08%; the six-hour daytime window, 0.68%. The lengths differ by a factor of three.
The same figures in equal six-hour blocks
To compare equal lengths, the 24 hours were split into four six-hour blocks. The sample is the same 69 trading days.
Open the table: Four six-hour blocks (4 rows)
| Block (JST) | Median absolute change | Days beyond ±1% | Median absolute change of hourly candles | Days on which the block had the largest change of the four |
|---|---|---|---|---|
| 9:00 → 15:00 (daytime observation window) | 0.68% | 42.03% (29/69) | 0.27% | 30 |
| 15:00 → 21:00 | 0.33% | 15.94% (11/69) | 0.19% | 6 |
| 21:00 → 3:00 next day | 0.77% | 34.78% (24/69) | 0.25% | 25 |
| 3:00 → 9:00 next day | 0.48% | 15.94% (11/69) | 0.19% | 8 |
Each block's change is calculated from the closes of the candles completing at the start and end of the block. The hourly change is the ratio of each candle's close to the close of the candle before it; each block has 414 candles.
Across the six-hour blocks, the median was 0.77% for 21:00 → 3:00 and 0.68% for the daytime window. The other two blocks were 0.33% and 0.48%, smaller than the daytime window.
Over the 18 hours of the overnight window, the median absolute change of hourly candles was 0.20% (1,242 candles). Over the six hours of the daytime window it was 0.27% (414 candles).
In six-hour blocks: 0.77% for 21:00–3:00, 0.68% for the daytime window, 0.48% for 3:00–9:00 and 0.33% for 15:00–21:00.
Measured by range
The other way to measure it is the range: the high-to-low span of each block as a share of the 24-hour high-to-low span.
For the 18-hour overnight window the formula is (overnight high − overnight low) ÷ (24-hour high − 24-hour low) × 100. The median was 83.17% and the mean was 80.01%.
Open the table: Share of the 24-hour range by block (5 rows)
| Block (JST) | Length | Median share of the 24-hour range |
|---|---|---|
| 9:00 → 15:00 (daytime observation window) | 6 hours | 59.45% |
| 15:00 → 21:00 | 6 hours | 35.03% |
| 21:00 → 3:00 next day | 6 hours | 51.89% |
| 3:00 → 9:00 next day | 6 hours | 35.45% |
| 15:00 → 9:00 next day (overnight window) | 18 hours | 83.17% |
The spans of the blocks overlap, so the shares do not add up to 100%. The share is not the part of the range formed only at night. Among the six-hour blocks, the daytime window's 59.45% was the largest of the four.
The share of the range was 83.17% for the 18-hour overnight window; among six-hour blocks the daytime window's 59.45% was the largest.
The days with the largest overnight change
From the 69 trading days, the top five by absolute change in the overnight window.
Open the table: The days with the largest overnight change (5 rows)
| Date (window start, JST) | Day | Overnight change | Daytime-window change on the same day |
|---|---|---|---|
| 2026-07-30 | Thu | +3.83% | +0.63% |
| 2026-06-11 | Thu | +3.77% | +2.89% |
| 2026-06-24 | Wed | +2.67% | -0.25% |
| 2026-08-04 | Tue | +2.47% | -0.32% |
| 2026-06-08 | Mon | +2.34% | -0.53% |
On three of the five days, the absolute change in the daytime window was below 0.6%. On 11 June the daytime window was also +2.89%.
The monthly breakdown, and what to keep in mind
Open the table: The monthly breakdown (5 rows)
| Month | Days counted (trading days) | Daytime-window median | Overnight-window median | Median overnight share of range |
|---|---|---|---|---|
| 2026-04 | 10 | 0.69% | 0.72% | 87.92% |
| 2026-05 | 13 | 1.04% | 0.87% | 83.17% |
| 2026-06 | 18 | 0.64% | 1.41% | 82.21% |
| 2026-07 | 17 | 0.84% | 1.49% | 66.75% |
| 2026-08 | 11 | 0.34% | 1.16% | 92.53% |
In May the daytime-window median, 1.04%, was above the overnight-window median, 0.87%. In the other four months the overnight window had the larger value.
There are two things to keep in mind. First, trading activity in this symbol grew a great deal over the period. The median trade count in the daytime observation window moves from 97 trades in April to 839.5 trades in August.
This count covers every weekday from Monday to Friday, 97 days in all. It includes holidays, so its days differ from the 69 trading days above.
Second, the original sample spans about four and a half months. Its statistics describe only that sample.
Update: 25 August to 24 September 2026
The following 19 Monday-to-Thursday observations use the same daytime observation window and overnight window defined above, each cut at the close of the hourly candle completing at 09:00 or 15:00 JST. They are separate from the original statistics.
"※" marks a Tokyo Stock Exchange holiday on the start date: 21, 22 and 23 September (3 rows). "†" marks a holiday on the next day: the rows for 21 and 22 September (2 rows). Source: Japan Exchange Group, Market Holidays, retrieved 16 October 2026.
Source: Hyperliquid public API, hourly candles (closing price). Retrieved 27 September 2026. Contract: xyz:JP225.
Each anchor uses the hourly candle completing at the stated time. Return = (end close / start close - 1) x 100, rounded to two decimal places for display. A value that rounds to 0.00% is shown without a sign.
Missing required anchor candles: 0. No interpolation.
Open the table: Update, 25 August to 24 September 2026 (19 rows)
| Start date (JST) | Daytime change | Overnight change |
|---|---|---|
| 2026-08-25 | +0.94% | -0.10% |
| 2026-08-26 | +0.86% | +1.23% |
| 2026-08-27 | -1.42% | 0.00% |
| 2026-08-31 | +1.98% | -0.48% |
| 2026-09-01 | +1.08% | -2.55% |
| 2026-09-02 | -0.54% | +0.36% |
| 2026-09-03 | -0.64% | +0.73% |
| 2026-09-07 | +0.17% | -0.47% |
| 2026-09-08 | -0.06% | -1.37% |
| 2026-09-09 | +0.43% | -1.00% |
| 2026-09-10 | +0.55% | -2.61% |
| 2026-09-14 | +0.68% | -0.60% |
| 2026-09-15 | +0.72% | +0.29% |
| 2026-09-16 | -0.02% | +1.60% |
| 2026-09-17 | -1.38% | +1.81% |
| 2026-09-21※† | +0.17% | +2.10% |
| 2026-09-22※† | -0.34% | +0.95% |
| 2026-09-23※ | -0.40% | -1.23% |
| 2026-09-24 | -0.61% | -0.21% |
These are perpetual-futures reference prices. The original statistics and the update cover separate periods.
Change log
2026-09-30: Added a chart of the four six-hour blocks near the top and folded the long tables. Changed the explanation of internal-pricing hours to match the three items in the specification (weekdays, weekends, holidays). Corrected the overnight value for 2026-08-11 in the holiday table to +0.43%.
Stated the sign rule for values that round to 0.00% and that the range share is not the part of the range formed only at night.
2026-09-29: Corrected the cut-off label from 15:30 to 15:00, the time actually used in the calculation. Separated the 8 days that touch a Tokyo Stock Exchange holiday and recalculated (77 days → 69). Added the six-hour comparison and the explanation of external and internal pricing.
Changed the heading and summary to match the new tables.
2026-09-27: Added 19 daily observations through 24 September and clarified window durations and the distinction from cash prices.
2026-09-20: Renamed the cash-session window to the daytime observation window, stated the cash session (morning and afternoon) and that the windows are aggregation windows, added the days on which trades were counted, and replaced the build date with the publication date.
Common questions
Q. Is this the movement of the Nikkei 225 itself?
A. No. It is the reference value of the Hyperliquid perpetual future xyz:JP225.
It can differ from the official value of the Nikkei 225.
Q. Are public holidays excluded?
A. They are separated from the statistics. The 8 days on which the start date or the next day is a Tokyo Stock Exchange holiday are listed in their own table.
Versions before 29 September 2026 counted 77 days, holidays included.
Q. How did the figures change from the previous version?
A. The overnight-window median went from 1.06% to 1.08%. The share of days on which it exceeded the daytime window went from 58.44% to 60.87%, and the share of range from 83.28% to 83.17%.
The daytime-window median is unchanged at 0.68%.
Q. Can it be said that the moves are larger overnight?
A. Not from this measurement. In six-hour blocks, only one block, 21:00 → 3:00, was larger than the daytime window.
Q. Why does the original sample cover four and a half months?
A. The source has a limit on how far back hourly candles can be retrieved. Coverage of this symbol begins on 9 April 2026.
Only the period that could be retrieved is used, with no interpolation.
Q. Will the night keep moving more from here?
A. The figures describe the stated sample period only. They do not forecast future returns.
Summary
- Across 69 Tokyo trading days, the median absolute change was 0.68% in the daytime window (9:00 → 15:00) and 1.08% in the overnight window (15:00 → 9:00 the next day).
- The overnight window exceeded the daytime window on 60.87% of days (42/69).
- In six-hour blocks, the medians were 0.77% for 21:00 → 3:00, 0.68% for the daytime window, 0.48% for 3:00 → 9:00 and 0.33% for 15:00 → 21:00.
- As a share of the 24-hour range, the median was 83.17% for the 18-hour overnight window and 59.45% for the six-hour daytime window.
- The original statistics cover April to August 2026, using Hyperliquid perpetual-futures reference prices.
Original-sample measurement note: the subject is 3,325 hourly candles of xyz:JP225, with 0 missing. Retrieval ends at 12:00 UTC on 25 August 2026.
How the figures were checked: a calculation written separately from the one used for the statistics recomputed the same figures from the saved hourly candles. All 22 items compared, including the number of trading days, the medians of the two windows and the medians of the four six-hour blocks, matched.
Reference prices appear on the 24-hour tab and on the Nikkei 225 symbol page. For the weekend measurement, see how much world share prices move at the weekend.
This article explains a mechanism and a measurement. It does not recommend any particular trade.
Source: Hyperliquid public API / Published: / Last updated: / Perpetual-futures prices are reference values.