Singapore Exchange (SGX) warned investors not to rely on data provided for the Straits Times Index, one day after a computer inaccurately reported the value of the component stocks in the benchmark index.
The incident is the latest in a string of computer-related problems to hit the exchange this year.
"The Straits Times Index (STI) may not reflect fully the movement in its components. Market participants are advised not to rely on the figure until further notice," the exchange said on its Web site Thursday morning.
However, the exchange soon issued another statement saying the problem had been resolved. "Straits Times Index correctly reflects the market prices of the components," it said.
The STI is an index of 50 companies traded on the Singapore stock exchange and is a widely used barometer for how the market is doing. On Wednesday morning, a computer problem at SGX caused the STI's value to be reported incorrectly. "The index was 3,376.06 at the noon trading break, when it should have been 3,437.36, which was a difference of 1.27%," SGX said in a statement.
Later on Wednesday, the exchange blamed the STI problem on a "computational error" and said the problem had been resolved. But the first statement from SGX on Thursday morning, advising traders and investors to not rely on the STI until further notice, indicated more work remained to be done.
SGX executives were not immediately available to comment.
The stock exchange has been hit by several computer glitches this year. In February and March, SGX had problems with its trading system, Singapore Exchange Securities Order Processing System (SESOPS). The system's display of order information slowed to a crawl under heavy trading volumes in February, and it was offline for more than an hour during trading in March.
At that time, SGX said it planned to upgrade its trading system, which remains in operation.