FORTUNE — On Monday, four and a half months after Carl Icahn tweeted that he had “pushed hard” for Apple (AAPL) CEO Tim Cook to use his company’s entire cash holdings to buy its own “extremely underpriced” shares, Wall Street’s most feared and admired corporate-raider-turned-activist-investor backed down.
Icahn’s announcement, made in an open letter to Apple shareholders on his Barbarian-at-the-Gates style newsletter, came the day after an influential proxy-advisory firm came down strongly against his shareholder proposal.
That proposal had already been scaled back (from $150 billion to $50 billion) and declawed (to non-binding status) when Cook pulled the rug out from under it by announcing that Apple had spent $14 billion in two weeks on a buyback spree that brought the company to within $18 billion of Icahn’s $50-billion-by-2015 goal — something it is on track to easily exceed before the end of the year.
But the recommendation by Institutional Shareholder Services was the kiss of death. Apple’s buyback rate may seem “like bailing with a leaky bucket” given the size of the company’s cash reserves, it wrote, but that wasn’t any reason to “micromanage” the company’s “good faith efforts.”
Icahn promised last summer when he first tweeted that he had taken a “large position” in Apple that he was in the stock for the long haul. Will he tweet to let the market know when he’s decided it’s time to sell?