THE Johannesburg stock exchange said on Tuesday that it is recalculating all the trading carried out late on Monday to correct “anomalies” in its backup system after technical problems halted the session. “Subsequent to this, the JSE was made aware of certain anomalies in the JET hot backup system and has had to declare all transactions affected after the opening of the second session to be void,” the JSE said in a statement. Earlier, the JSE said it will open two hours late at 11am on Tuesday, but pre-market pricing was available. The JSE halted trade for around 45 minutes late on Monday due to technical problems.