Icahn is ending his crusade after months of railing against Apple's eight-member board in television interviews and posts on his Twitter account.
The barbs didn't seem to be winning Icahn many allies.
The California Public Employees' Retirement System, a major Apple shareholder, had already dismissed Icahn's proposal as unnecessary meddling and the influential shareholder advisory firm Institutional Shareholder Services weighed in Sunday with a report recommending a vote against Icahn's idea.
New York City Comptroller Scott M. Stringer, who manages pension funds that own 2.5 billion Apple shares, joined in the criticism of Icahn in a Monday letter to the company's stockholders.
"As long-term shareowners, we believe the proposal is a short-sighted and unnecessary attempt to boost Apple's current stock price at the expense of its long-term financial flexibility and value creation potential," Stringer wrote.
Institutional Shareholder Services said Apple could be doing more to generate better returns from its cash, but concluded the board has made enough "good-faith efforts" to be trusted to look out for stockholders' best interests.
"The board's latitude should not be constricted by a shareholder resolution that would micromanage the company's capital allocation process," ISS wrote in its recommendation against the proposal. The advisory firm said Apple is on track to spend about $32 billion buying back its stock during the current fiscal year.
AP Business Writer Tom Murphy in Indianapolis contributed to this story.