Aflac ( AFL) downgraded at Barclays from Equal-weight to Underweight. $20 price target. Valuation call, based on the company's book value. BJ Services ( BJS) downgraded at Barclays from Overweight to Equal-weight. $13 price target. Pressure pumping market will likely remain weak through 2010. Brocade ( BRCD) upgraded at Goldman Sachs to Buy from Neutral. Expect higher Street estimates and multiple expansion as Cisco pushes into server market. Shares are still down 37% in 2009, leaving additional upside as a result of improved competitive position. Price target raised to $6.50 from $3.75. Caterpillar ( CAT) upgraded at JPMorgan from Neutral to Overweight. $40 price target. Company's liquidity position is improving, and 74% earnings recovery is possible next year. Carnival ( CCL) downgraded at Wachovia. Rating lowered to Market Perform from Outperform. Maintains $25-$27 valuation range and 2009 EPS estimates of $2.20. Clear Channel ( CCO) downgraded at Goldman Sachs to Sell from Neutral. View recent rally as overdone in light of deterioration in outdoor advertising and lack of visibility into turnaround. Also note likely covenant breach at parent company. Price target maintained at $2.50. Comerica ( CMA) downgraded at Citigroup to hold from buy as Citi believes the near term risk/reward is relatively balanced at these levels. Price target increased to $24 from $18 largely due to lower equity risk premium. Bull case is strong capital base (and low risk of dilution) and normalized earnings power of $3.50,implying 'intrinsic value' of roughly $35 -- in line with many banks. However, CMA has large commercial portfolio which raises near term risks as entering into commercial end of the credit cycle given losses can be lumpy.