According to analyst Jetstream Research, Amazon (AMZN.US) appears undervalued as its stock has underperformed the S&P 500 over the past year, presenting a compelling entry opportunity for long-term investors. The analyst assigned a 'Strong Buy' rating, citing robust revenue growth and expanding operating cash flow margins driven by AWS and advertising, the two fastest-growing segments with substantially higher margins than core e-commerce. Over the past twelve months, Amazon generated $743 billion in revenue (a 14% year-over-year increase), with 59% from North America, 23% from International, and 18% from AWS. Although AWS accounts for only 18% of total revenue, it contributes approximately 56% of operating profit, with its higher margin lifting Amazon’s overall operating margin from below 5% a decade ago to over 11% today. Advertising and AWS both posted year-over-year growth rates well above 20%. Investments in custom-designed chips and robotics are expected to enhance profitability long term, potentially enabling operating cash flow growth to outpace revenue growth. Amazon’s stock is trading at a historically low price-to-operating-cash-flow ratio.