But the only news that could account for the tech giant's massive drop is far less rational, writes MoneyShow's Jim Jubak, also of Jubak's Picks.

Shares of Apple (AAPL) have sold off by 4.76% today (for a drop of $27.43 a share) as of 3:30 p.m. New York time. Why?

Well, Apple is one of those stocks that is so widely held as part of so many strategies that it is quite capable of sinking or soaring on internal market dynamics. (In other words, there might not be a “real world” reason beyond traders doing what some computer has told them would make money.)

But there is a piece of news out today, which might be the cause of the drop in the stock’s price. If that news is actual cause of the drop, the interpretation of that news is startlingly wrong. Boneheaded. Innumerate.

See what you think. (Apple is a member of my Jubak’s Picks portfolio.)

Here’s the news: Technology market researcher IDC projected today that by 2016, the tablet market would reach annual sales of 283 million units by 2016. That’s huge growth from the company’s projection of 122 million units in 2012. And it represents an 8.1% increase in IDC’s earlier forecast.

You’d think that would be good for Apple, the market share leader in tablets. Except that, as IDC also projects, Apple will lose share in the tablet market from now through 2016.

Apple’s share of the tablet market, IDC projects, will fall to 49.7% in 2016 from—ready for the bad news?—56.3% in 2011 and a projected 53.8% in 2012. Google (GOOG), meanwhile, will see its share increase to 42.7% in 2012 from 39.8% in 2011. By 2016, Google will drop back, however, to a 39.7% share of the market.

Let’s leave aside the issue of whether IDC or anyone else can really predict market share down to one decimal place for 2016 and do a few calculations with these numbers.

Here’s the bad news for Apple: The company will sell a projected 66 million iPads and iPad minis in 2012, when it holds a 53.8% market share. In 2016, when Apple’s share is projected to have dropped to 49.7%, the company will sell 141 million units.

Yes, the terrible news is that because the tablet market is forecast to grow to annual sales of 283 million units in 2016 from 122 million in 2012, Apple’s slightly smaller market share (49.7% from 53.8%) results in growth from 66 million units sold in 2012 to 141 million in 2016.

Yep, I see exactly why financial markets decided to sell Apple lower today.

Some traders would probably argue that today’s projections on market share represent a cut in expectations for Apple’s market share and tablet sales. That would make sense of me if Apple were a high-flying technology momentum rocket that traded at 60 times earnings.

But Apple’s trailing-12-month price-to-earnings ratio is just 12.43. That’s only 80% or so of the price-to-earnings ratio for the average S&P 500 stock.

If I could convince the market to grant me a wish, it would be that traders sell Apple back down to the $525 or so the stock hit on November 14. I’d be happy to buy at that price—again—and then sell two weeks later at the $589 or so the stock hit on November 26. In fact, I’d be happy to do that over and over again.

So go ahead and sell. Give me my wish. Make my day.

Full disclosure: I don’t own shares of any of the companies mentioned in this post in my personal portfolio. The mutual fund I manage, Jubak Global Equity Fund, may or may not now own positions in any stock mentioned in this post. The fund did own shares of Apple as of the end of September. For a full list of the stocks in the fund as of the end of September, see the fund’s portfolio here.