Does the stock exchange have certain times that it is open at to buy and sell shares? For example between 9AM and 9PM every day. Or is it open 24 hours a day, 7 days a week?
I am more interested in information about stocks and shares in the United Kingdom.
Thanks for your time.

March 10th, 2010 at 5:28 am
The US markets open from
09:30 – 16:00 (EST)
For UK markets open from
07:00 – 15:30 (GMT)
Markets are closed Sat, Sun, and most major holidays.