GT Advanced Technologies (NASDAQ: GTAT) shares are trading sharply lower following AppleInsider concerns and comments from CLSA analyst Mark Heller.

AppleInsider

According to AppleInsider, the rumored 5.5 inch iPhone is facing production issues, which may push back launch to 2015. GT Advanced Technologies is expected to produce a the front panel for the device, which is supposedly one of the parts Apple (NASDAQ: AAPL) is having trouble with. AppleInsider says the concern involves touch screen sensitivity.

CLSA

Mark Heller of CLSA slashed his estimates of GT Advanced Technologies’ sapphire product revenue by 50 percent on production difficulties. Although Heller expects Apple to continue to incorporate the firm’s technology, he says straightening out production will take time.

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The note also stated that GT Advanced Technologies will not produce sapphire for the upcoming iWatch, although much of Wall Street disagrees.

Price Action

GT Advanced Technologies has been one of the most controversial companies on Wall Street as investors speculate on the amount of integration the company will have with Apple. Although shares are down 6.3 percent Monday morning, the company’s value has risen by 64.5 percent in 2014. Shares were last trading at $15 on high volume.