The Australian Securities Exchange (ASX) was forced to cease trading at 2.48pm yesterday due to an IT systems issue.
The glitch affected confirmation messages for trades, meaning the exchange had to be closed down, as trades could not be conformed as having taken place.
The exchange was unable to resume trading yesterday, but is expected to open today. An estimated $A1.5 billion in trades were unable to be made.
The ASX installed a new trading system, ASXTrade, in November.