Corporate raider Carl Icahn revamped his proposal Tuesday for embattled computer company Dell, calling for a big share buyback in a plan which would keep the company public. Icahn, who has lambasted a go-private plan led by founder Michael Dell as undervaluing the company, said he and his investor allies would vote against that proposal and urged shareholders to consider his alternative. Under his plan, Dell would make a tender offer for $14 per share for approximately 1.1 billion Dell shares. The offer is intended to account for approximately 72 percent of shares outstanding, Icahn said. The price of such an offer would top the $13.65 per share offered by Dell and investment fund Silver Lake Partners that would take Dell private in a $24.4 billion transaction. \"Our proposal allows those who believe, like us, that the $13.65 price being offered in the Michael Dell/Silver Lake going private transaction significantly undervalues Dell, to continue to hold Dell shares,\" said Icahn in an open letter to shareholders. A Dell spokesman said the Dell\'s board\'s special committee would continue to oversee the process. \"We remain focused on our customers and on providing innovative products and solutions to help them succeed and better compete,\" the Dell spokesman said. Icahn also disclosed that he has purchased 72 million additional shares from Southeastern Asset Management, which has also been active in Icahn\'s campaign. Together, Icahn and Southeastern own approximately 13 percent of Dell shares, Icahn said. Icahn and Southeastern agreed not to participate in the tender offer. Icahn\'s latest offer follows his most recent plan for Dell to grant shareholders $12 a share from Dell\'s cash and new debt and retain their equity stake. In a previous plan, Icahn offered $15 per share for up to 58 percent of Dell shares. 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. A special committee of Dell\'s board on June 5 endorsed the Michael Dell proposal \"as the best option for shareholders\" and faulted the Icahn plan for having a $3.9 billion potential funding shortfall. Icahn\'s letter Tuesday said he was working to obtain $5.2 billion of senior debt financing to be made available to Dell. A major investment bank has agreed to $1.6 billion in funding and Icahn and his affiliates would supply an additional $2 billion, Icahn said. Icahn reiterated his call for shareholders to reject the Dell go-private proposal at a July 18 special meeting to vote on the plan.