The following ratings changes were generated on Thursday, March 12.We've upgraded automotive parts retailer Advance Auto Parts ( AAP) from hold to buy, driven by its revenue growth, good cash flow from operations, expanding profit margins, solid stock price performance and notable return on equity. We feel these strengths outweigh the fact that the company is trading at a premium valuation based on our review of its current price compared to such things as earnings and book value. Revenue rose by 13.7% since the same quarter a year ago, though earnings per share declined by 25.7%. We feel the company is poised for EPS growth in the coming year in spite of reporting somewhat volatile earnings recently. Net operating cash flow increased by 214% to $102.9 million compared with the year-ago quarter, outperforming the industry average. AAP's gross profit margin of 48.2% is strong, though it has decreased from the year-ago period. Its net profit margin of 2% compares favorably with the industry average. Shares have risen over the past year, outperforming the S&P 500, despite the company's weak earnings results. The stock's price rise over the last year has driven it to a level which is somewhat expensive compared to the rest of its industry, but we feel that other strengths this company displays justify these higher price levels We've downgraded Ameriprise Financial ( AMP), which provides financial planning, asset management, and insurance services, from hold to sell, driven by its deteriorating net income, disappointing return on equity, generally disappointing historical performance in the stock itself and feeble growth in its earnings per share.