Nasdaq recently announced, starting December 6, new trading hours from 9:00 pm to 4:00 am, effectively increasing the trading day to 23 hours (with one hour available for settlement operations).
This reinforces the trend which has seen investors demand longer trading hours outside the traditional exchange daytime hours, with many markets now available 24 hours a day.
The 24-hour trading periods
The 24 hour trading day however is not one continuous trading period: for example the US stock market operates across four primary trading periods each weekday, spanning the full 24-hour cycle across major exchanges, like NYSE and Nasdaq, and Alternative Trading Systems (ATS).
Each period has its own characteristics and mechanics which investors need to be aware of:
| Trading Period | Time (US Eastern Time) | Key Characteristics & Mechanics |
| Pre-Market | 4:00 AM – 9:30 AM | Volatility is often high as traders react to overnight news, European market activity, and pre-bell corporate earnings reports. |
| Regular Trading Hours (RTH) | 9:30 AM – 4:00 PM | The core session offered directly by primary exchanges. Peak liquidity, tightest bid-ask spreads and highest execution volume occur during this window. |
| After-Hours (Post-Market) | 4:00 PM – 8:00 PM | Commences right after the closing bell. Most US earnings announcements release immediately after 4:00 PM, driving significant price movement. |
| Overnight | 8:00 PM – 4:00 AM | Operated via dark pools and specialized ATS (e.g., Blue Ocean ATS). Trades execute Sunday through Thursday nights, primarily using limit orders for select liquid equities and ETFs. |
The new Excel formulas
To cater for this shift towards 24 hour trading we have recently added some new Excel formulas which enable you to retrieve prices for each of these periods, as well as a new general formula which will return the “24 hour” price.
(All of these formulas have corresponding change and change % formulas):
| Trading Period | Excel Price Feed Formula |
| Pre-Market | EPF.Yahoo.PreMarketPrice |
| Regular Trading Hours (RTH) | EPF.Yahoo.Price |
| After-Hours (Post-Market) | EPF.Yahoo.PostMarketPrice |
| Overnight | EPF.Yahoo.OvernightMarketPrice |
| 24 hour (automatically switches between periods) | EPF.Yahoo.Price24h |
EPF.Yahoo.OvernightMarketPrice
This new formula returns the overnight market price, in this case from Blue Ocean ATS via Yahoo Finance.
EPF.Yahoo.Price24h
This new formula returns a price regardless of the time of day and currently active trading session. This is really useful if you want your spreadsheet to be easily updated any time of the day with just one formula for the price.
See our User Guide for full details of the Excel Formulas.
The formulas in action
We have also added these formulas to our sample spreadsheet
Here is Dell stock during the pre-market session: you can see that the pre market price (571.70) and 24 hour price (571.70) are available. The regular market price (578.96) is the close price of the previous days regular market session:
We hope you find these new formulas useful.
