Editor's Note: TheStreet ratings do not represent the views of TheStreet's staff or its contributors. Ratings are established by computer based on metrics for performance (which includes growth, stock performance, efficiency and valuation) and risk ( volatility and solvency). Companies with poor cash flow or high debt levels tend to earn lower ratings in our model. NEW YORK ( TheStreet ) -- Citigroup (NYSE: C ) has been upgraded by TheStreet Ratings from hold to buy. The company's strengths can be seen in multiple areas, such as its increase in net income, attractive valuation levels, solid stock price performance and growth in earnings per share. We feel these strengths outweigh the fact that the company has had generally high debt management risk by most measures that we evaluated. Highlights from the ratings report include:.