Each weekday, TheStreet.com Ratings updates its ratings on the stocks it covers. The proprietary ratings model projects a stock's total return potential over a 12-month period, including both price appreciation and dividends. Buy, hold or sell ratings designate how the Ratings group expects these stocks to perform against a general benchmark of the equities market and interest rates. While the ratings model is quantitative, it uses both subjective and objective elements. For instance, subjective elements include expected equities market returns, future interest rates, implied industry outlook and company earnings forecasts. Objective elements include volatility of past operating revenue, financial strength and company cash flows. AnnTaylor Stores ( ANN) is a specialty retailer of women's apparel, shoes and accessories. It has been upgraded to a buy from a hold. The company has no debt to speak of, and has a largely solid financial position. It has reported somewhat volatile earnings recently, but TheStreet.com Ratings believes it is poised for EPS growth in the coming quarters. AnnTaylor's gross profit margin of 55.30% is rather high, although its net profit margin of 5.20% trails the industry average. The company had been rated a hold since August 2007. Arkansas Best ( ABFS) provides motor carrier transportation services in the U.S. It has been downgraded to a hold from a buy. The company's debt-to-equity level of 0.03 is below that of the industry average, implying that there has been very successful management of debt levels. It also has an adequate quick ratio of 1.20, which illustrates the ability to avoid short-term cash problems. However, Arkansas Best's revenue declined by 4.4% in the second quarter compared with the same period last year, which has contributed to an earnings decline of 30.98% in the same timeframe, to 78 cents a share from $1.13 per share in the second quarter last year. Its net operating cash flow also decreased 20.19% to $41.30 million during that period. Arkansas Best had been rated a buy since July 2007. China Petroleum & Chemical ( SNP) operates as an integrated oil and gas, and chemical company in the People's Republic of China and Hong Kong. It has been downgraded to a hold from a buy. The company's revenues increased by 9.8% in the second quarter compared with the same period last year, outpacing the industry average of 3.0%. China Petroleum's return on equity of 23.72% in the second quarter marked an improvement from the same period last year, a clear sign of strength within the corporation. However, as a counter to these strengths, TheStreet.com Ratings finds that the company has not been very careful in the management of its balance sheet. China Petroleum had been rated a buy since October 2005.