Dell's special board committee reviewing a sale of the computer giant asked corporate raider Carl Icahn on Monday for more information on his offer, saying details of the bid were too vague.
"It is not clear to us whether you intend to formulate your transaction as an actual acquisition proposal that the board could evaluate," a letter released by Dell said.
"We would need certain clarifications and additional materials."
The letter said the committee would need "comprehensive information" on financing, including any commitments for loans.
It added that the proposal unveiled last week "does not appear to take into account the additional borrowings that would seem to be required" for the company.
The proposal by Icahn and other investors including Southeastern Asset Management, also lacked details on contingencies, such as what would happened "if the transaction is not consummated."
Icahn and the other dissident shareholders, in making the offer last week, called the planned buyout unveiled earlier this year a "giveaway."
The investor group, which holds around 13 percent of Dell shares, said in a regulatory filing it would urge shareholders to reject the private equity buyout and opt instead for its "superior" recapitalization plan, keeping the company public.
Icahn has allied with Southeastern to block the plans led by Michael Dell, with the investment fund Silver Lake Partners, to take Dell private in a $24.4 billion -- or $13.65 a share -- buyout.
Icahn, who initially offered $15 per share for up to 58 percent of Dell shares, unveiled the new plan, which would inject fresh capital and keep the company publicly traded in what is known as a leveraged recapitalization.
Under the Icahn plan, shareholders would get $12 a share, from Dell's cash and new debt, and retain their equity stake.
Icahn, in a letter to shareholders also filed with the Securities and Exchange Commission, did not place a value on the offer, but said it "is superior to the going private transaction."
In unusually harsh language, the document called the buyout plan "the great giveaway" and "insulting to shareholders' intelligence."
"The going private transaction leaves all of the upside to Michael Dell and an opportunistic buyout group with only their own interests in mind," the letter said.
Icahn is known for hostile bids and efforts to take over companies he sees as undervalued.
Dell unveiled plans to go private in February, giving founder Michael Dell a chance to reshape the former number one PC maker away from the spotlight of Wall Street.
The move, which would delist the company from stock markets, could ease some pressure on Dell, which is cash-rich but has seen profits slump, as it tries to reduce dependence on the slumping market for personal computers.