Proxy advisory firm ISS on Tuesday recommended shareholders of Hewlett-Packard Co vote against the re-election of HP's board chairman and two other directors because of their role in the costly 2011 acquisition of software company Autonomy.
The purchase of Autonomy led to a massive writedown for HP and ISS said shareholders should reject Chairman Ray Lane and board members John Hammergren and G. Kennedy Thompson.
"While developments surrounding the 2011 Autonomy deal may continue in the coming months, it is clear that the due diligence process that occurred at that time was not robust," ISS said in a report.
It said that executive chair Lane, the finance and investment committee's Hammergren and Thompson "bear the most responsibility for a very costly oversight failure."
Last month, a union pension adviser said it would campaign against Hammergren's and Thompson's re-election to the board, though it said it would not oppose Lane because of the risk of disruptions were he to leave.
HP shares rose 2.1 percent to $20.39 in morning trading.
(Reporting By Ben Berkowitz; Editing by Gerald E. McCormick and Grant McCool)