HP said it welcomed any intervention from the authorities. "The same fertile imagination that was behind a massive fraud is apparently still hard at work making up stories. We would encourage Mr Lynch to spend as much time as possible with the authorities," it said.
Mr Lynch said the document suggests the US company had not yet determined whether hundreds of millions of transactions were improperly booked at the time it took its huge charge on Autonomy.
It showed "unambiguously that the writedown was driven by accounting policy changes and differences, not fraud", he said.
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The document, which was being worked on at the time of the writedown, reveals HP calculated that Autonomy had improperly booked $350m worth of revenue generated through contracts with customers between 2010 and the first three quarters of 2011.
Separately, in November 2012, John Schultz, HP's general counsel, said about $200m of Autonomy deals had been "created" over a two-year period beginning in 2009.
According to the document, whole categories of deals were considered illegitimate. Transactions were placed under labels ranging from "not IFRS compliant confirmed", where HP believed the numbers did not meet UK accounting standards, to "management judgment/US GAAP difference", where HP believed they did not meet the requirements set by US GAAP accounting standards.
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