Australia's anti-trust regulator apologised "unreservedly" for publishing confidential information about its decision to block a $15 billion merger of TPG Telecom and Vodafone Australian, blaming a flaw in its website.
The Australian Competition and Consumer Commission's decision to reject the deal was uploaded to its website an hour before the market closed on May 8, catching investors unawares as they were expecting a decision on the next day.
The news sent both firms into a tailspin and shares slid across the broader sector until the market closed and the regulator published a fuller note explaining its reasons.
The information was being input into the back end of the mergers registry ahead of time, in keeping normal practice, when "a third-party user sought to access the existing webpage at the precise moment it was being updated," the ACCC said.
"Instead of the new information being treated as draft content requiring internal approval, the flaw meant the content was live for eight minutes," the regulator said in a statement on Thursday.
"We apologise unreservedly for this unfortunate and serious incident," ACCC Chief Operating Officer Rayne de Gruchy said.
He added the regulator's technology team had fixed the software glitch, promising the incident would not be repeated.
The $15 billion deal was to combine the third and fourth-largest telcos in Australia to create a big player boasting TPG's fibre network and Vodafone's mobile system.
The firms have said they will contest the rejection in court.