The following ratings changes were generated on Tuesday, March 10.We've downgraded property and casualty insurer Chubb ( CB) from buy to hold. Strengths include its largely solid financial position with reasonable debt levels by most measures and notable return on equity. However, we also find weaknesses including weak operating cash flow, poor profit margins and a decline in the stock price during the past year. Chubb's debt-to-equity ratio is very low at 0.3 is currently below the industry average, implying very successful management of debt levels. Revenue fell by 12.6% but still outperformed against the industry average, since the same quarter a year ago, and EPS decreased. Chubb's 19.7% gross profit margin is rather low, having decreased from the year-ago quarter. Its 13.3% net profit margin significantly outperformed the industry average. Net operating cash flow decreased by 36.1% to $400 million since the same quarter a year ago. We've downgraded CB Richard Ellis Group ( CBG) from hold to sell, driven by its deteriorating net income, generally weak debt management, disappointing return on equity, poor profit margins and weak operating cash flow. Net income decreased from $122.5 million in the same quarter last year to -$1.1 billion, significantly underperforming the S&P 500 and the real estate management and development industry. The 25.7 debt-to-equity ratio is very high and above the industry average, implying very poor management of debt levels, and the 0.7 quick ratio demonstrates the company's lack of ability to cover short-term liquidity needs. Return on equity has greatly decreased compared with the year-ago quarter, a signal of major weakness within the corporation. The 12.2% gross profit margin is extremely low, having decreased from the year-ago quarter, and the 84.9% net profit margin is significantly below the industry average. Net operating cash flow decreased 57.6% compared with the year-ago quarter to $101 million.