Although he still opposes Dell’s bid, Icahn said “it would be almost impossible to win” and will not make any more efforts to block the deal.
Along with major investor Southeastern Asset Management, Icahn argued that the $24.8 billion (£15.8bn) offer by chief executive Dell and private equity firm Silver Lake undervalues the company.
In a letter to shareholders, Icahn said: “The Dell board, like so many boards in this country, reminds me of Clark Gable’s last words in Gone With The Wind, they simply ‘don’t give a damn’.”
Shareholders are due to vote on Thursday, and Dell’s founder needs about 42 per cent of investors to support his bid.
Once the world’s largest computer maker, Dell and its rivals have been fighting an uphill battle as more consumers switch to mobile devices. Last month it posted its seventh consecutive fall in quarterly profits, with a 72 per cent plunge to $204 million.