NEW YORK -- A battle for U.S. computer giant Dell (IW 500/20) heated up Friday as corporate raider Carl Icahn and other investors made a new offer and called a planned buyout led by company founder Michael Dell a "giveaway."

The investor group, which holds around 13% 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 Asset Management to block plans announced this year and 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% 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.

The dissident investors would offer a new slate of directors if the current board refuses to back the plan.

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."

Claim: Buyout Undervalues Tech Firm

In unusually harsh language, the document called the buyout plan "the great giveaway" and "insulting to shareholders' intelligence."

It said the buyout undervalues Dell and "amazingly allows him to purchase the company from shareholders with their own money."