North American iPhone sales to fall 10%: Firm

Apple shares are down 16 percent from mid-July highs despite the launch of the next iteration of the iPhone. The stock underperformed again Thursday, falling 1 percent as the rest of the market rose.

Shares of suppliers to the iPhone maker fell even more Thursday, with names like Skyworks and Avago posting declines of greater than 2 percent.

A report from boutique investment firm Detwiler Fenton may be why.