BEA Systems has shot back at billionaire investor Carl Icahn's demand for a shareholder vote on Oracle's $6.7 billion takeover bid.

"The Board and management of BEA Systems are not opposed to an acquisition of the company. In fact, we are currently exploring ways to maximise shareholder value, including the possible sale of the company," the company said in a letter to Icahn.

The board repeated its argument that Oracle's $17 per share offer, which expired Sunday, was too low. BEA has asked for $21 per share but received no takers, or indeed any other public bids at all. Oracle's offer was worth $6.7 billion, as opposed to the approximately $8.3 billion BEA wants.

BEA emphasised that it is open to being acquired. "It is important that there be no misunderstanding of the Board's position. We are opposed to selling the company at $17.00 per share. We are not opposed to selling the company."

Icahn is BEA's largest shareholder. He said in a statement Friday that he had filed suit in Delaware to force a shareholder meeting. He wants BEA's board to hold an auction sale, at which shareholders could consider offers from the highest bidder.

To that end, Oracle did not rule out further bids in a statement released Sunday: "The BEA shareholders should not assume that Oracle will renew its $17 per share offer in the future. Over time many things can change: BEA's business might materially weaken, the stock market can fall further from its recent record highs, or Oracle may have committed its capital elsewhere."

BEA users have speculated over what might happen to the company's middleware technologies, should a sale to Oracle or another party go through.