May 14, 2013 - Market data vendor Bloomberg has suffered another blow to its credibility as it emerges that more than 10,000 confidential client memos sent through its private messaging system have been pubished online.

The data - which includes messages scraped from traders at more than a dozen of the world's largest banks - was mistakenly uploaded by a former employee in 2009 and remained freely-available through a simple Google search until earlier this week.

The latest setback follows revelations earlier this week that Bloomberg reporters were using the company's $20,000 per year Professional terminals to eavesdrop on client log-ins.

Bloomberg CEO Daniel Doctoroff sought to draw a line under the scandal on Monday by admitting the 'mistake' and creating a new role of client data compliance officer to tighten up procedures.

News of the latest leak of condfidential client data will be further damaging to the company, which is facing the prospect of deeper investigations by regulators and central banks in the EU and US.