The following ratings changes were generated on Friday, Dec. 19. We've upgraded property and casual insurance company CastlePoint Holdings ( CPHL) from sell to hold. Strengths include its robust revenue growth, good cash flow from operations and notable return on equity. However, we also find weaknesses including deteriorating net income and poor profit margins. Revenue leaped by 62.8% since the same quarter last year, outperforming the industry average of 6.6% growth, though earnings per share declined. Net operating cash flow has increased to $51.24 million, or 42% compared with the same quarter last year, vastly surpassing the industry average cash flow growth rate of -12.26%. CastlePoint underperforms both the S&P 500 and the industry average on the basis of return on equity. The company's gross profit margin is extremely low at 2.6%, having decreased significantly from the same period last year, and its net profit margin of -10.7% is below the industry average. Net income decreased from $10.5 million to -$13.15 million, underperforming the S&P 500 and the insurance industry. We've downgraded Gruma ( GMK), which manufactures and distributes corn flour, tortillas, wheat flour and related products, from hold to sell, driven by its deteriorating net income, disappointing return on equity, poor profit margins, generally disappointing historical performance in the stock itself and feeble growth in its earnings per share. Net income decreased from $72.2 million to -$164.4 million compared with the same quarter a year ago, significantly underperforming the food products industry as well as the S&P 500. Return on equity has also greatly decreased from the same quarter one year prior, a signal of major weakness. Gruma's gross profit margin is currently lower than what is desirable at 33.10%, having decreased from the same quarter the previous year, and its the net profit margin of -19.10% is significantly below that of the industry average.