Time period just before or immediately following normal exchange trading whereby trades can take place over electronic communications networks (ECN). In the US, the periods are typically weekdays between 8am - 9:30am and 4pm - 6:30pm.
Related information about extended trading:
- Extended Hours Trading - NASDAQ.com
 Extended Hours Trading - NASDAQ offers extended trading activity including   most active stocks in the after hours pre-market trading sessions.
 
- After Hours Trading | Afterhours Stock Market Quotes - NASDAQ.com
 Investors find that After-hours trading activity provides a leading indicator for next-  trading day activity as well as insight into Global Markets trading activity, ...
 
- Pre-Market Most Active Stocks - NASDAQ.com
 Premarket Most Active Stocks - Includes Ten Most Active Share Volume, Ten   Most Advanced, Ten Most Declined ... NASDAQ - Pre-Market Ten Most Advanced ...
 
- Extended Trading Definition | Investopedia
 Trading conducted on electronic exchanges either after regular trading hours are   over or before they begin. Usually such trading is limited in its volume ...
 
- After-Hours Trading: Understanding the Risks
 Nov 4, 2008 ... Before you decide to trade after-hours, you need to educate yourself about the   differences between regular and extended trading hours, ...
 
- Extended Hours Trading Questions & Answers - American Century
 What is extended hours trading? What are the extended trading hours? Why is   American Century Investments® brokerage offering extended hours trading?
 
- Extended Hours Stock Trading - Scottrade
 Following are the regular and extended trading hours for U.S. markets: Normal   Market Day. 7 to 9:28 a.m. ET Pre-Market Hours 9:30 a.m. to 4 p.m. ET Regular ...
 
- TSC's</I> Guide to Extended Trading Hours - TheStreet
 Oct 8, 1999 ... After-hours trading is a thing of the present Here's what you need to prepare for   the night shift.