Canaccord analyst Michael Graham upgraded Amazon.com (AMZN) to Buy from Hold and raised his price target for the shares to $750 from $600. The online marketplace giant closed yesterday up $13 to $534.10. After "regrettably" missing last year's rally, Graham sees the 25% pullback in Amazon shares year-to-date as a buying opportunity. The company's core eCommerce business should continue to benefit from secular shifts, the analyst tells investors in a research note.