TheStreet) -- CHANGE IN RATINGS American International Group ( AIG - Get Report) was rated new buy at Bank of America/Merrill Lynch. $37 price target. Stock is trading at a discount to expected, year-end book value. Black Hills ( BKH - Get Report) was upgraded to outperform from neutral at Credit Suisse. Attractive valuation with solid growth prospects. Price target trimmed by a dollar to $33. Cracker Barrel ( CBRL - Get Report) was downgraded from outperform to market perform at Morgan Keegan. Company is seeing slower sales and could be hurt by rising commodity costs. CME Group ( CME - Get Report) was upgraded from neutral to buy at UBS. $318 price target. Company has cyclical and secular growth potential. Geenrac ( GNRC - Get Report) was rated new outperform at Oppenheimer. $23 price target. Company can deliver strong organic growth and generate steady cash flow. Micron ( MU - Get Report) was upgraded from market perform to outperform at Wells Fargo. Estimates also boosted, given higher memory contract prices. Noble ( NE - Get Report) was upgraded from market perform to outperform at Morgan Keegan. $48 price target. Stock has pulled back, even though the company is seeing better contract awards. Under Armour ( UA - Get Report) was upgraded from hold to buy at Stifel Nicolaus. $80 price target. New products should help drive growth. MEMC Electronic ( WFR) was downgraded from buy to hold at Stifel Nicolaus. Solar wafer business is rapidly deteriorating. Zale ( ZLC) was downgraded to neutral from buy at Bank of America/Merrill Lynch. Limited upside after recent rally. Price target raised to $6.75. End of report.