Southeastern Asset Management, the activist investor that owns 8.4 percent of Dell Inc, said on Tuesday that the computer maker's evaluation of a $24.4 billion leveraged buyout deal with its founder and buyout firm Silver Lake was flawed.

Southeastern published a letter it sent to Dell's board of directors asserting that the company's proxy statement released on March 29 fails to make a case for shareholders to accept the $13.65 per share offer of Michael Dell and Silver Lake and that Dell's special committee did not properly explore all options.

Citing excerpts from Dell's proxy statement, Southeastern said the company did not properly explain why it did not entertain a buyout offer that would allow shareholders to elect whether they wanted to be paid in cash or stock. It urged Dell's special committee to negotiate now "in good faith."

Dell has received two alternative buyout proposals from Blackstone Group LP and billionaire investor Carl Icahn that it has said could be expected to result in superior offers.

(Reporting by Greg Roumeliotis in New York; Editing by Gerald E. McCormick)