The London Stock Exchange says human error, rather than foul play, caused an outage at its Turquoise trading platform in November that resulted in a delayed technology migration.
The LSE quickly identified human error as the cause of the two hour outage on 2 November but also raised the spectre of sabotage, claiming "preliminary investigations indicate that this human error may have occurred in suspicious circumstances".
It launched an internal investigation and called in the Financial Services Authority and police.
In a brief statement, omitting any mention of "suspicious circumstances", the group now says: "The investigation found the incident was the result of human error and the incident has now been closed."
Turquoise had migrated to a new trading platform from recently acquired vendor MillenniumIT the month before its outage and the main market was set to follow in mid-November.
However, the incident, along with network upgrades, saw this put back and the exchange has now told customers that the migration is now expected to happen on 14 February.