The following ratings changes were generated on Friday, Oct. 17. We've downgraded AK Steel Holding ( AKS) from buy to hold. Strengths include its revenue growth, largely solid financial position with reasonable debt levels by most measures and notable return on equity. Weaknesses include poor profit margins, weak operating cash flow and a generally disappointing performance in the stock itself. Revenue grew by 19.6% since the same quarter one year ago, trailing significantly the industry average of 72.2% but still boosting EPS. The 0.51 debt-to-equity ratio is low and below the industry average, implying successful management of debt levels. The company also maintains an adequate quick ratio of 1.06, which illustrates the ability to avoid short-term cash problems. AK Steel's gross profit margin of 15.4% has decreased from the same quarter last year and is rather low. Its net profit margin of 6.5% significantly trails the industry average. Net operating cash flow has decreased to $161.20 million, or 36.70%. In addition, when comparing the cash generation rate with the industry average, the firm's growth is significantly lower. We've downgraded Quest Diagnostics ( DGX), which provides diagnostic testing, information and services that enable physicians and other healthcare professionals to make decisions to improve health, from buy to hold. Strengths include the company's revenue growth, higher earnings, higher cash levels, sound leverage, and key business initiatives. Weaknesses include declining operating margin and diminishing returns. In addition, frequent changes in laws and regulations in the U.S. may negatively impact the company's future performance. Quest Diagnostics' net second-quarter sales advanced 12%, with the acquisition AmeriPath adding about 8.1% to the growth. Revenue increased to $1.84 billion from $1.64 billion a year ago. Revenue from clinical testing rose 12.4% to $1.68 billion, while revenue from other operating segments climbed 8.3% to $161.41 million. Revenue per requisition increased 7.1%, and clinical testing volume, measured by the number of requisitions, rose 4.9%. Cash and cash equivalents jumped to $143.40 million from $122.30 million in the comparable quarter of last year. The debt-to-equity ratio improved to 0.89 from 1.23 as total debt declined and shareholders' equity increased 15% to $3.67 billion.