A familiar name does not mean the same instrument
A regular stock index and a chart labeled CFD or after-hours must be read separately. A cash index aggregates constituent stocks under a defined methodology. A CFD is a derivative based on price differences, and a perpetual future is not the index itself. The site's 24h category contains different types of extended-hours data. Open each chart's explanation instead of assuming every instrument in the category works alike.
Put the Nikkei 225 beside its after-hours counterpart, or the S&P 500 beside S&P 500 CFD, to observe related prices after the cash session ends. A regular index remaining CLOSED while the after-hours line moves is not necessarily a malfunction. The charts represent different markets or instruments.
Extended hours do not mean identical conditions all day
After-hours data helps you observe markets beyond the regular stock session. It does not mean every instrument trades continuously every day of the year. Instrument schedules, weekends and maintenance can interrupt trading. Participation and liquidity can also differ outside cash hours, allowing relatively little trading to produce a larger price move. Check both the session indication and the update status.
The derivative price can differ from the cash index because of product design, supply and demand, links to futures and trading terms. Perpetual futures may also involve funding payments. This board is not a trading terminal displaying every fee and contractual detail. If you trade, verify executable prices, costs and rules with the service you use.
The comparison may use the related cash-market close
For after-hours instruments configured with a cash-market reference, this site generally uses the previous trading session's close while that market is open, and its latest close while it is closed. Consider an illustrative index with a prior close of 100, today's close of 102 and an after-hours price of 103. During the cash session the comparison is with 100; after today's close is confirmed, it is with 102.
This makes the distance from the latest regular close easier to see. It does not necessarily use the derivative's own prior close or represent the same comparison period as the cash index's change. When the reference switches, the percentage can change without a large move in the instrument itself. Quote arrival or close confirmation can be delayed, so read the status alongside the number.
Observe changes; do not treat them as tomorrow's opening price
A rising after-hours price does not guarantee that the cash market will open higher by the same amount. Subsequent news, currencies, other markets and opening orders can change the picture. Use the two charts to investigate what changed after the close rather than to obtain a guaranteed forecast. Sunday USD/JPY likewise moves separately from regular USD/JPY and does not guarantee its reopening price.
CFDs and perpetual futures involve risks including leverage, sharp moves and risks associated with their counterparties or structure. Watching an index and trading its derivative are different activities. Use the board for observation and comparison, and do not substitute one product for another simply because the names resemble each other. The public guidance below discusses general CFD risk; the site's disclaimer explains the use of its information.
Display behavior checked on October 4, 2026. Examples are illustrative, not investment advice. See the disclaimer.