NEW YORK (Reuters) - Billionaire activist investor Carl Icahn said Thursday he had sold his entire stake in Apple Inc (>> Apple Inc.), citing the risk of China's influence on the stock.

Icahn, in an interview with cable television network CNBC, also said he was "still very cautious" on the U.S. stock market and there would be a "day of reckoning" unless there was some sort of fiscal stimulus.

Icahn had been a huge cheerleader of Apple, acquiring a stake in the company almost three years ago, repeatedly calling the investment a "no brainer."

In an open letter to Apple Chief Executive Officer Tim Cook in May 2015, Icahn had argued that shares of the iPhone maker were worth $240, about 90 percent more than they had been trading. At $240 a share, Apple's market cap would be $1.4 trillion, Icahn asserted.

But Icahn, who owned 45.8 million Apple shares at the end of last year, said China's economic slowdown and worries about how China could become more prohibitive in doing business triggered his decision to exit his position entirely.

"We no longer have a position in Apple. Tim Cook did a great job. I called him this morning to tell him that and he was a little sorry, obviously. But I told him it's a great company," Icahn said. "In Apple today as opposed to six months or a year ago, in this one, there’s no need for activism because I think they have a great management. But you worry a little bit, maybe more than a little, about China's attitude."

Asked when he might get back in, Icahn replied: "I don’t think it’s the price point. I think it's my opinion about what is happening with China. I think the stock is very cheap on a multiple basis. China could be a shadow for it, and we have to look at that."

Icahn, who suggested that he made roughly $2 billion off the Apple trade, said he was in Apple for about three years and "if you bought the stock then, you got a 48 percent to 50 percent total return. We obviously made a great deal of money, but it was no surprise that we got out of some in February."

Apple shares came under further selling pressure during Icahn's television interview, as did the Dow Jones industrials with Apple closing down over 3 percent at $94.83. The Dow ended down by 210 points.

Apple on Tuesday posted its first decline in iPhone sales as well as its first revenue drop in 13 years. The company's sales fell by more than a quarter in China, its most important market after the United States, and it forecast another disappointing quarter for global revenues.

Apple shares have now declined more than 10 percent this week.

(Reporting by Sam Forgione; Editing by James Dalgleish, Jennifer Ablan and Bernard Orr)

Stocks treated in this article : Apple Inc., Cheniere Energy, Inc.