In October, Apple stock dropped below 600 for the first time since July. Since then, following a number of new product launches, AAPL has continued to fall and now only sits slightly higher than last week at roughly 550 per share and a market cap of $518 billion. While many have pointed to uncertainty regarding new product launches and executive level changes as the cause of Apple’s falling share price, no one quite has a definitive answer for why AAPL has hit a nearly six-month low. In a report today, titled “A dramatic reading of Apple’s share price”, Asymco analyst Horace Dediu might have the answer.

Dediu studied 13 bear AAPL markets starting with the October 2001 launch of the iPod. As noted in the report, Apple’s stock had just fallen 70 percent year-over-year and continued to drop another 20 percent following the iPod launch. However, since the iPhone launch, Dediu found “every dramatic drop in share price was followed by a surge in earnings growth.” The graph above maps earnings growth following bear Apple markets since the 2007 iPhone introduction.

So, why exactly does this happen? Dediu explained his theory:

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One could even say the worse the bear, the better the growth. Sounds completely counter-intuitive, but there is some perverse logic in this as well. The market reflects crises (as well as over-abundance) of confidence. Unforeseen growth is what creates wealth and the crisis in confidence is a reflection of the improbability of continuing out-performance. When Apple’s performance is foreseeable the stock moves slowly upward. When its performance is unforeseeable the stock moves dramatically downward.

A pithy way of putting it is: No news is good news. Good news is bad news.

When a product is understood the stock is mildly desirable. When a new product appears the future is hazy and the stock is undesirable. But that haziness hides potential but up and down. New products is what innovators produce. Bizarre new products is what disruptors produce.

In other words, the paradoxical observation in the chart above of “the more drama in the market, the more success in the marketplace” makes sense when inverted.

For disruptive companies, it should be “the more success in the marketplace, the more drama in the market.”

In that sense the current downdraft may be quite auspicious.

The Wall Street Journal has a theory that “tax-induced selling is one factor some market watchers attribute to the recent declines, including stumbles in highfliers such as Apple, which has tumbled 8.1% this month.” The graphic below shows what some AAPL investors are facing with possible higher taxes on capital gains.

(via Fortune)

Update 12:30 EST: Apple’s general counsel Bruce Sewell and board member Arthur Levinson have sold close to 10,000 and  7,500 shares of AAPL stock, respectively.