The London Stock Exchange has offered no detailed technical explanation to the markets about its four hour trading outage today.
As the exchange successfully came back online at 12.15, LSE chief executive Xavier Rolet - who brought in the venue's new Millennium trading system - apologised "sincerely" for the issues.
The LSE declined to comment on what happened to the systems this morning or what exact technology was affected. It said only that the problem had been a "real time data dissemination issue". Earlier this week, the LSE also refused to explain an outage on its Borsa Italiana venue in Milan, which led the Italian market regulator to demand immediate details on what would be done to prevent another occurrence.
Large market data vendors, supplying LSE price information to traders, have been experiencing severe data accuracy issues over the last two weeks. Privately, they have expressed immense frustration that the problems are occurring, but so has the exchange. It remains unclear where the problems originate - even though they pervade through different levels of the data-to-market supply chain.
Rolet today issued a statement apologising for the outage and insisting that this morning's technology problem had been solved. "We sincerely regret the inconvenience that today's disruption to trading has caused our customers," he said. "We have resolved the real time data dissemination issue and our UK cash equity markets have now resumed trading."
The problem was first announced at 7.54 this morning, as trades were cancelled on the system. Market sources speaking to Computerworld UK said the issue was also visible even earlier than that.
"The uncrossing trades that took place in the opening auction today are under investigation for potential cancellation," the LSE said as the problems unfolded.
Millennium Exchange, the platform newly running on the main venue of the LSE, is written in C++ language and runs on Novell SUSE Linux-based datacentres. It offers data through the FIX and ITCH protocols.
Millennium replaces the TradElect system, based on Microsoft .Net and written in C#. Rolet began to distance the exchange from TradElect only a matter of weeks after becoming chief executive in 2009. An outage on that system two years earlier had lasted all day, leaving furious city brokers unable to trade on the city's main venue.