HP has extended the deadline for its $11 billion (£6.7 billion) takeover offer for UK software firm Autonomy after just 41.62 percent of shareholders accepted the bid.

The first closing date for the offer passed yesterday, and shareholders will now have until 10am on 3 October to vote in favour of the takeover.

HP announced its plans to acquire Autonomy for £25.50 per share on 18 August, with the approval of both companies' boards. The Autonomy board of directors, led by founder and CEO Mike Lynch, has also unanimously recommended its shareholders accept the offer.

TechMarketView analyst Richard Holway was surprised by the low shareholder acceptance level.

"The £25.50 per share offer for Autonomy really looked 'top of the range'," he said.

"Nobody really expected a rival bid to top that, so it's a bit surprising that the acceptances to date are not higher. I still don't see any rival bid as likely - but never say never."