Britain's Serious Fraud Office (SFO) has closed its investigation into the ill-fated sale of Autonomy to Hewlett-Packard Co in 2011, saying there was not enough evidence to secure a conviction of the software firm's former executives.
Autonomy was supposed to be the $11.1 billion centerpiece of a shift into software for HP, but the deal turned sour a year later when it wrote off three quarters of the company's value.
HP alleged "some former members of Autonomy's management team used accounting improprieties, misrepresentations and disclosure failures" to inflate the company's apparent worth by more than $5 billion.
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Autonomy's former management, including company founder Mike Lynch, has denied the allegations.
HP, based in Palo Alto, California, said it passed information supporting its claims from an unidentified whistleblower to the U.S. Department of Justice, the Securities and Exchange Commission and the SFO.
The SFO, which started its investigation in early 2013, said: "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."
It said it had ceded jurisdiction over other aspects of the case to U.S. authorities, whose investigation is ongoing.