On CNBC.com's quote page, during the extended hours session times outlined above, an additional quote strip will be visible that displays the real-time extended hours quote, the change from the most recent regular market session close (4p ET), as well as the extended hours volume and time stamp for either pre-market or after hours.
The bottom strip will contain the 4p ET regular session close for easy comparison. This layout makes it very easy to view impact to a company by any late breaking or pre-market news events providing an indication of how the stock will perform in the regular market session.
Extended Hours Data is provided by NYSE Arca Last Sale and the NASDAQ Last Sale Feeds. Quotes do not necessarily represent the best bid or ask in the marketplace.