The following ratings changes were generated on Monday, March 16.We've downgraded Cogent ( COGT), which provides automated fingerprint identification systems and other fingerprint biometrics solutions to governments, law enforcement agencies, and other organizations worldwide, from buy to hold. Strengths include company's its robust revenue growth, compelling growth in net income and good cash flow from operations. However, we find that the stock itself is trading at a premium valuation. Revenue leaped by 82.8% since the same quarter last year, greatly exceeding the industry average of 10.1% growth. Net income rose 49.3%, from $7.7 million to $11.5 million, significantly outperforming the S&P 500 and the electronic equipment, instruments and components industry. Cogent's 57.4% gross profit margin is rather high, though it has decreased significantly from the same period last year. EPS improved significantly compared with the year-ago quarter, but we anticipate underperformance in the coming year relative to the company's two-year pattern of positive EPS growth. We've downgraded East West Bancorp ( EWBC), which operates as the holding company for East West Bank, from hold to sell, driven by its disappointing return on equity, poor profit margins, weak operating cash flow, generally disappointing historical performance in the stock itself and deteriorating net income. Return on equity has greatly decreased compared with the same quarter a year ago, a signal of major weakness within the corporation. The 22.1% gross profit margin is rather low, having decreased significantly from the year-ago period. Net operating cash flow fell 39.3% to $38.1 million, compared with the year-ago quarter. Net income decreased by 93.6%, from $37.3 million to $2.4 million.