The Serious Fraud Office has ended its investigation into the $11.1 billion (£7.3bn) sale of software firm Autonomy to HP, following allegations of accounting improprieties.
It had been claimed that the British firm, led by former CEO Mike Lynch, had misled HP over the value of its business prior to the 2011 acquisition. HP subsequently referred the case to regulators in the UK and US in 2013.
The SFO said on Monday that, in respect to some aspects of the allegations, there is insufficient information available for a realistic prospect of a conviction and so would drop its case.
"In respect of other aspects and on the application of well-established principles, jurisdiction over the investigation has been ceded to the US authorities whose investigation is ongoing," a statement read.
The SFO did not provide details on which parts of the investigation against Autonomy CEO Lynch and ex-chief financial officer, Sushovan Hussain, will be passed to the US Justice Department.
Both Lynch and Hussain deny wrong-doing, and have made claims that HP is attempting to cover up its own mis-management following the deal.
HP said in a statement that it would continue to cooperate with US investigators, and "remains committed to holding the architects of the Autonomy fraud accountable".
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