Bank of America Merrill Lynch downgraded shares of Apple on Friday following the iPhone make's disappointing earnings report.

Apple shares traded sharply lower in premarket trading, a day after the company reported disappointing data on shipments of iPhones for the last quarter and revenue guidance that also fell short of Wall Street expectations. The company also said it would no longer break out unit sales numbers for the iPhone, iPad and Mac.

The bank downgraded Apple to neutral from buy, citing four reasons:

slower growth in app store revenue, especially in China

guidance for the December quarter that implies weaker-than-expected iPhone unit sales

investors will likely interpret ending iPhone unit sales figures as negative

weaker growth in emerging markets because of the stronger dollar

"We see increased risk from a weaker macroeconomic environment," analyst Wamsi Mohan said in the note. "Post results we are incrementally concerned that not all the weakness is capture in N/T [near term] and we are likely to see further negative estimate."

The analyst also lowered his 12-month price target to $220 from $235.

Apple shares dropped 5.7 percent to $209.41 in premarket trading Friday.

— With reporting by CNBC's Michael Bloom