Three of the Singapore Exchange's (SGX's) main public websites were down for about an hour yesterday afternoon.
Trading in both securities and derivatives was not affected.
Listed companies were unable to upload their announcements during that period, while Central Depository (CDP) account holders were not able to log in and view their accounts.
From about 1pm to 2.20pm, www.sgx.com, SGXNet and CDP.com went offline because of issues sustained by a third-party service provider, an SGX spokesman said.
But few appeared to have noticed the outage, although SGX said it put out tweets on when the problem occurred and when the websites came back online.
The SGX spokesman declined to identify the third-party service provider involved.
The Straits Times understands that apart from SGX, other customers of the third-party service provider were also affected.
On April 17, a data connectivity glitch on Fidelity National Information Services' SunGuard systems disrupted trading of several equity traders connected to FIS' system for several hours.
The SGX said in a statement that at 10.40am that day it sent a message to brokers that it had been informed by technology provider FIS that FIS was facing securities market-data issues, and was working at resolving the issues.
The SGX said that there were no issues observed at SGX's infrastructure, and securities and derivatives trading was as per normal.
The matter was resolved by 2.35pm that day.