Amazon.com ( AMZN) upgraded at Citigroup from Buy to Hold. $97 price target. Company's operating margins are coming back faster and sales growth may be sustainable longer than previously expected. Cheesecake Factory ( CAKE) downgraded at Goldman Sachs to Neutral due to recent 77% price appreciation since March 11. Recommended long CAKE/short PFCB trade resulted in 31% relative performance gain. Expect upward revisions in estimates for CAKE, but note that valuation appears extended. Price target at $13. Capital One ( COF) downgraded at Goldman Sachs to Neutral from Buy due to likely extended weakness in credit card into 2010. Note rising delinquencies and preference for DFS. Price target lowered to $17 from $18. City National ( CYN) downgraded at Goldman Sachs to Sell from Neutral due to likely weakness in quarterly pre-provision results caused by asset sensitivity and asset management results. Price target trimmed to $30 from $35. Discover Financial ( DFS) upgraded at Goldman Sachs to Buy from Neutral, Goldman said. Note attractive valuation, track record of book valuation growth, and TCE/TA ratio of 8.4%. Company will continue to receive Visa/Mastercard settlement payments during a tough 2009. Price target upped to $12 from $6.50. Energizer Holdings ( ENR) downgraded at UBS. Rating lowered to Sell from Neutral. Price target raised to $53 from $40. 2009 EPS estimates raised to $5.40 from $5.31. King Pharmaceuticals ( KG) upgraded at UBS from Sell to Buy. $10.50 price target. Expect a higher probability of Skelaxin settlement with SGP. Quicksilver Resources downgraded to sector perform from outperform and price target reduced to $9 from $10 at RBC. Downgrade based on tight liquidity, near term covenant risk and relative valuation.