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Apple shares were clubbed again yesterday after the company lowered revenue guidance for the upcoming quarter. The stock lost 10% yesterday—the biggest single day drop in six years. The shares are down 38% from their high last year, translating into a $450 billion loss in market value.

Apple pointed the finger at China, but there is more to the story than the weakening of Asia’s biggest economy. A saturated smartphone market, missteps in select emerging markets, and a major mistake on pricing are all parts of Apple’s problem.

We have long harbored doubts about Apple’s ability to sustain strong margins in a fiercely competitive and historically deflationary industry.

Below is some of our research from last year on Apple.