THE Johannesburg Stock Exchange said on Friday that its pre-open session, when orders can be entered before trade opens, will start 15 minutes earlier from January 31 following a rise in trading volumes. The bourse said in a statement that the pre-open session will now start at 8.25am. A bourse spokesman said the pressure for a longer pre-open came mostly from firms operating Internet trading sites, which had seen a boom in business. “These companies are getting 400-500 orders. It was physically impossible to enter all the orders in the given time,” the spokesman said.