Historically, there has been only one market session (or contiguous period of time) during the day in which the market was open. However, for many institutional and professional investors, there was always some speculation and shuffling of unexecuted orders to ECNs or non-U.S. markets after the U.S. market closed. As the Internet became more commercialized, these "after market" venues became popular alternate markets.
Today, numerous online broker-dealers offer access to after market sessions that begin sometime after the traditional market close and continue until late in the evening.
The regular trading session is 9:30 a.m. to 4:00 p.m. Eastern Standard Time (EST) Monday through Friday (except federal holidays). Orders placed near or after market close will be cancelled or rescheduled depending on the Time In Force selected when the order was placed. The full array of securities is offered during the traditional market session including listings from the New York and American stock exchanges and the NASDAQ stock market.
The regular market session is regulated by the Securities and Exchange Commission (SEC) and by the NASD Rules of Fair Practice. We abide by these regulations.
The Pre-Market session hours are 8:00 a.m. to 9:30 a.m. EST.
The Post-Market session hours are 4:00 p.m. to 6:00 p.m. EST.
These times are relevant on days in which the regular market session is open, except when the market closes early.