The fact that the overall stock market has risen convincingly in the face of Apple’s sharp drop raises questions about the predictive power of a stock that was once investors’ darling.

“The company just isn’t the market bellwether,” Paul Hickey, co-founder of Bespoke Investment Group, tells The New York Times.

Since Jan. 2, Apple shares have plunged 18 percent, while the Standard & Poor’s 500 Index has climbed 3 percent.

Editor's Note: How You Lost $85,000 During the Last Decade. See the Numbers.

Apple also hasn’t correlated much with the overall market when the stock has soared, Hickey says. His data show IBM is the real market leader.

During the last 10 years, on the day after IBM announced earnings, the S&P 500 matched the direction moved by its stock 75 percent of the time.

That represents the highest score for any company in the index, and is twice Apple’s 37.5 percent.

To be sure, Princeton economist Burton Malkiel says the stock market generally doesn’t move in a predictable manner.

“If it did, money managers would be able to beat the market regularly. But the vast majority of them can’t,” he tells The Times.

In any case, not everyone has turned bearish on Apple’s shares.

“This is still a fantastically successful company, and the stock is dirt cheap by almost any measure,” writes MarketWatch columnist Brett Arends.

“The company is basically sitting on $100 billion in cash or equivalents.”

Editor's Note: How You Lost $85,000 During the Last Decade. See the Numbers.