Apple suppliers are seeing strange things happen to their share prices

Something strange has happened this year between Apple and companies that supply parts to its many products: Their stock performances have diverged, after a long period of moving up and down together. Even weirder is that this divergence is not based on which companies are more dependent on the tech giant.

Shares of major suppliers that generate significant portions of their revenue from Apple have held relatively steady despite Apple's stock getting crushed in the last few weeks. In fact, some of them even have outperformed Apple significantly over the longer run.

Year-to-date shares of Cirrus Logic, for example, are up roughly 13 percent as of the market's close Tuesday. The company develops high-precision analog and mixed-signal integrated circuits for a broad range of innovative customers including Apple.

Likewise, shares of Multi-Fineline Electronix, a company that provides printed circuit and assembly solution, are also up close to 7 percent. Compare that with Apple's stock, which is down over 11 percent in the period.

Both Cirrus Logic and Multi-Fineline Electronix generate more than 70 percent of their revenue from Apple. The divergence in stock performance is counterintuitive given Apple's lackluster Q1 2016 growth and lowered Q2 revenue guidance.

Surprisingly, other companies that have a more diversified supply chain have moved in line with Apple's stock recently and even underperformed the stock over the longer term.

For instance, InvenSense is down 25 percent since Apple reported earnings two weeks ago. The chip supplier's stock was punished Tuesday when it missed analysts' revenue expectations for the fourth quarter. Skyworks, too, is down 8 percent in the past two weeks and shares of Jabil Circuit and Broadcom are down close to 3 percent.

This contrasts with Apple shares' decline of more than 11 percent in the period. All four aforementioned companies get less than 30 percent of their revenue from Apple.

While some stocks may be mispriced, experts believe that the impact already has been seen on the supply chain from Apple's lowered numbers across companies highly dependent on Apple's business.

Supply chain indicator

Brian Blair, a principal investor from Grays Peak Capital whose company tracks Apple, told CNBC that most major suppliers already reported earnings before Apple and many of them reported weak June guidance numbers that broadly matched Apple's own second-quarter guidance.

While their stocks weren't punished as badly, Apple's suppliers remain cautious about the second half of the year given uncertainty about sales of the yet-to-be released iPhone 7.

The best way to gauge Apple's future strength is to pay attention to the performance of these suppliers, Blair said.

"What we are doing at Grays Peak is paying a lot of attention to the supply chain," he said. "We are trying to understand what exactly is happening there. That is going to be the best indicator of what's going to occur."

Asked whether he is inclined to put money to work in companies that rely on Apple or others more diversified, Blair told CNBC that he prefers those that are more diversified and tied to emerging technologies segment, such as voice and voice-interface, where he sees growth, thus looking at companies that provide microphones, audio features and other related products.