Icahn told CNBC in September that he thought the stock was incredibly cheap and that Wall Street does not fully appreciate Apple.
"I think Apple is still ridiculously underpriced," Icahn said in September.
David Einhorn's Greenlight Capital also said it trimmed its Apple stake in the fourth quarter amid a decline in the value of the iPhone maker's shares.
Among other 13F filings, Adage Capital Partners reported holding 8.1 million Apple shares at the end of last year, down 5 percent from Sept. 30. Blue Ridge Capital held 2 million Apple shares at year end, down 11 percent from Sept. 30.
Tiger Global Management, however, reported a new position in Apple, with 10.6 million shares as of Dec. 31.
Apple's stock has been under pressure, having fallen more than 15 percent in the last three months, according to FactSet. The company also had a mixed first-quarter earnings report in January with EPS beating estimates, but revenue falling short.
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— Reuters contributed to this report
CORRECTION: An earlier version of this article misrepresented when Carl Icahn cut his stake in Apple.