Stock Upgrades, Downgrades From TheStreet.com Ratings

Each weekday, 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 forecasted company earnings. Objective elements include volatility of past operating revenue, financial strength and company cash flows.

Shipping company Navios Maritime(NM Quote) has been upgraded to a hold from a sell. The company's revenues jumped 107% in the first quarter of fiscal 2007 compared with the same quarter a year ago. This growth seems to have trickled down to the bottom line, improving earnings per share. Analysts are expecting more EPS gains in the future. Navios Maritime's stock price has nearly doubled in the past 12 months. NM had been rated a sell since February 2006.

Real estate investment trust Simon Property Group(SPG Quote) has been downgraded to a hold from a buy. The company specializes in owning regional malls and shopping centers. Net income fell slightly in the first quarter of fiscal 2007 from the year-earlier period, resulting in a decline in earnings per share. The company's debt-to-equity ratio is currently very high at 4.34, suggesting there has been poor management of debt levels within the company. Simon Property Group had been rated a buy since May 2005.