Tiffany remains a company that has one of the most bulletproof and inimitable brands, and fourth quarter results and guidance suggesting accelerating sales growth underline the solid underpinnings and staying power of the Tiffany name. Tiffany’s brand is the key driver of our narrow economic moat rating, which denotes the view of the sustainability of the company’s cash flows. The company now believes it will return to growth in 2013 (mid-single digits), and diamond pricing trends and stability in inventory growth suggest to us that a more normal environment in 2013 is a reasonable assumption. Although most analysts agree with…