Updated The Serious Fraud Office has retracted its probe into the sale of Autonomy to HP in 2011 on grounds that the information presented to it provides "insufficient evidence for a realistic prospect of conviction".
The investigation began in early 2013, following a referral from HP. In 2012, the company alleged Autonomy had "outright misrepresented" its value - leading to a $8.8bn (£5.8bn) writedown from HP.
The body responsible for investigating and prosecuting serious and complex fraud said in order not to undermine the US-based investigation it was "unable to go into further detail at this stage regarding the basis of these decisions."
"In respect of some aspects of the allegations, the SFO has concluded that, on the information available to it, there is insufficient evidence for a realistic prospect of conviction," said the regulator.
Jurisdiction over the investigation has been ceded to the US authorities, whose investigation is ongoing, it said.
The SFO re-iterated its own use of an HP Autonomy product did not amount to a conflict of interest. "Throughout the investigation we have kept the potential for conflict of interest under review. Such a conflict of interest does not exist, nor has it ever existed, and the matter played no part in any decision concerning this investigation," it said.
Former Autonomy boss Mike Lynch – has consistently denied any wrongdoing. ®
HP has been in touch since the publication of this story to say:
HP remains committed to holding the architects of the Autonomy fraud accountable. As the SFO made clear, the US authorities are continuing their investigation and we continue to cooperate with that investigation.
Mike Lynch responded:
We welcome the SFO's decision to close its investigation. As we have always said, HP's allegations are false, and we are pleased that after a two-year review of the material presented by HP, the SFO has concluded that there is not a case to pursue. Let's remember, HP made allegations of a $5 billion dollar fraud, and presented the case in public as a slam dunk. HP now faces serious questions of its own about its conduct in this case and the false statements it has made.
US regulator the Securities and Exchange Commission declined to comment as to when a ruling is expected.