HP made the statement after the technology equipment leasing firm Comdisco said it had agreed to sell its technology services division, known as Availability Solutions, to SunGard for $825m (£569m).
Comdisco filed for bankruptcy in July, blaming the downturn in the economy. The company said it would sell its technology services business unit to HP for $610m, although the deal would be conditional on "higher or otherwise better offers".
Any other offer besides that made by HP had to be made during the court-authorised auction, according to Comdisco spokeswoman Mary Moster.
Comdisco's agreement with SunGard came after the auction and is subject to approval by a Chicago bankruptcy court, which will hold a hearing on 23 October.
In August, SunGard offered $775m for Comdisco's technology services unit. But, Moster said, because Comdisco could only accept offers that had been made in the bankruptcy court auction, it was unable to accept the bid.
It is unclear why SunGard's final bid was $825m, $50m more than its initial offer. Another company may have made a higher bid than SunGard's initial bid, but Moster said she couldn't comment because the bids submitted during the auction were confidential.
In a statement, HP said the US Department of Justice (DOJ) was investigating the proposed sale to SunGard. HP also said the DOJ decided not to open an investigation into its proposed acquisition of Comdisco.
Moster said Comdisco was aware of the DOJ's investigation. "We have the support of the Official Creditors' and Equity Committees, and Comdisco concluded that SunGard's offer was the highest or otherwise best offer," she said. The committees represent Comdisco's creditors.
HP, however, disagreed.
"[HP] expects to be confirmed the successful bidder and to participate in the 23 October bankruptcy court sale, and it expects to be confirmed the successful bidder given the anti-competitive nature of SunGard's proposed acquisition," the company said in a statement.
HP stressed that its bid to acquire Comdisco was pro-customer and pro-competition, and that it planned to integrate most assets of Comdisco's technology unit into the HP Operations segment of its HP Services division.
SunGard spokeswoman Kelly O'Brien said it was SunGard's policy not to comment on the competition. She also said the company would not speculate on the bankruptcy court proceedings because it is an ongoing process.
"We are confident our bid will prevail and we look forward to closing as soon as possible," she said.