Each business day, 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. However, the rating does not incorporate all of the factors that can alter a stock's performance. For example, it doesn't always factor in recent corporate or industry events that could affect the stock price, nor does it include recent technology developments and competitive dynamics that may affect the company. For those reasons, we believe a rating alone cannot tell the whole story, and that it should be part of an investor's overall research. The following ratings changes were generated on June 27 Monolithic Power Systems ( MPWR) designs, develops and markets analog and mixed-signal semiconductors and has been upgraded to Buy. The revenue growth came in higher than the industry average of 20%. Since the same quarter one year prior, revenue rose by 45%. MPWR reported significant earnings per share improvement in the most recent quarter compared to the same quarter a year ago. The company has demonstrated a pattern of positive earnings per share growth over the past two years. We feel that this trend should continue. During the past fiscal year, Monolithic Power turned its bottom line around by earning 22 cents vs. a loss of 9 cents in the prior year. This year, the market expects an improvement in earnings ($1.05 vs. 22 cents). The net income increased by 1,904% when compared to the same quarter a year ago, rising from a loss of $330,000 to $5.94 million.