Before Standard & Poor's lowered its credit outlook on Warren Buffett's Berkshire Hathaway ( BRKA), TheStreet.com Ratings recommended that investors "hold" the stock despite analysts' predictions of an earnings rebound. Berkshire shares are trading at 15 times this year's projected earnings, suggesting limited return potential in a depressed stock market. The Omaha, Neb.-based company maintains C-range grades from TheStreet.com Ratings due to stock-price volatility and return potential. Analysts expect Berkshire's profit to rise 75% this year from dismal levels in 2008. Per-share earnings at the investment company led by the legendary billionaire had climbed steadily in recent years, hitting $8,547 in 2007. But last year, earnings sank by 62% to $3,224 on falling revenue. Analysts forecast $5,562 a share in profit this year, followed by a 14% increase to $6,450 next year. S&P revised its ratings outlook for Berkshire to "negative" from "stable," citing diminished capital in its insurance operations caused by stock-market declines. Berkshire's class A shares have fallen about 8% this year, trading between $85,000 and $90,000. TheStreet.com Ratings' evaluation model analyzes a company's stock value, financial data (based on Generally Accepted Accounting Principles) and expected earnings growth based on analysts' estimates. The "performance rating" suggests a stock's return potential while the "risk rating" reflects its price volatility. High grades in those categories result in strong "overall ratings." Grades for most companies range from A-plus to E-minus, with bankrupt firms assigned marks of F.