The London Stock Exchange is investigating the cause of a five hour outage at its Refinitiv market data unit on Thursday morning.
Refinitiv's Eikon platform went out at around 07:30 GMT, leaving the firm's 400,000 end users unable to access prices for currencies and other assets. Other services hit included FXall and the World-Check One AML screening tool.
The issue was fixed shortly after mid-day, with the firm embarking on an internal investigation into the cause, which apperas to have been triggered by a problem with authenticating users as they logged in
The LSE completed its $27 billion takeover of Refinitiv in January in an effort to create a serious rival to Bloomberg in the financial data sector. However, its shares have been on a downward slide after it admitted that it would have to spend more time and cash on the integration effort than initially expected.