Activist investor Carl Icahn and Southwest Asset Management have joined forces to buy Dell in a move that put Silver Lake Partners and founder Michael Dell in the backseat.

Silver Lake and Dell are offering $24.4 billion for the company, the equivalent of $13.65 a share. Icahn, Southwest and other investors believe that the firm is worth more, so they submitted an alternative proposal that would allow shareholders to hold on to their stock and take an additional $12 a share in cash or stock. That may sound tempting, but Dell is not buying it.

A special committee working on behalf of the company demanded more details about the bid in a response published in WSJ this week. The letter specifies that Icahn and Southwest have not yet proven that their offer is an “actual acquisition proposal.”

Dell has every reason to be cautious about the bid. The company’s ongoing privatization was initiated after Michael Dell reached the conclusion that it cannot regain its competitive edge and meet investors’ near-term expectations at the same time – in his view, the choice is either going private or going broke.

Dell’s attempt to make a comeback is two-pronged: the firm is trying to transform its business model and overhaul its offerings portfolio at the same time. In the enterprise, Dell is eyeing software-defined infrastructure. The company acquired Enstratius, a provider of on-demand software for managing hybrid clouds, earlier this month. On the consumer side, the vendor is trying to revive its presence in the mobile market. Dell is betting much of its reputation on Project Ophelia, a USB-size gadget that can transform any HDMI-compatible monitor into an Android device. The product will become available in July for a cool $100.