The Singapore Exchange says the software error that delayed the opening on Wednesday of the local stock market was caused by "programming changes performed over the weekend."

Its disclosure follows the Monetary Authority of Singapore's statement registering its "disappointment and concerns" with SGX over the delayed opening on Wednesday of the local stock market caused by a software defect.

The Singapore Exchange announced at about 4am on Wednesday that it will delay the stock market opening on Wednesday to 12:30pm because of a software glitch that has since been rectified.

SGX said the delayed opening is to enable member firms to complete client position reconciliations, and rectify any errors in the end-of-day processing for Monday, December 1, 2014, on the securities client-accounting system hosted by SGX on behalf of dealers.

A reader LH Teo asked why there had been no mention of the Dec 1 problem earlier.

SGX said in itss second statement on Wednesday that it has been in regular communication and is working closely with its members firms to advance the end-of-day processing for trading to commence at 1230 hrs.

SGX said that all securities post trade online systems, including the client-accounting system (CAS) hosted by SGX on behalf of member firms, have been available to its members since 0600hrs. This is to enable member firms to complete client position reconciliations, and rectify any errors in the end-of-day processing in the CAS for 1st December 2014.

SGX has been in regular communication and is working closely with its members firms to advance the end-of-day processing for trading to start at 12.30 pm.