AN accounting watchdog has opened an investigation into the software company accused of misleading investors prior to its multi-billion dollar takeover by American giant Hewlett-Packard.

The Financial Reporting Council will examine Cambridge-based Autonomy's books in the period between January 2009 and June 2011 – three months before it was bought by the US firm in a £7.1 billion deal. HP recently wrote off £5.1bn from quarterly earnings, with the majority linked to its accusations of "serious accounting improprieties, misrepresentation and disclosure failures" at Autonomy.

Referring the matter to the Serious Fraud Office, the American firm alleged in November that former members of Autonomy's management fiddled accounts in a bid to "mislead investors and potential buyers".

Autonomy founder Dr Mike Lynch, who pocketed around £500 million from the HP takeover, has denied the allegations.