AXP) upgraded at FBR from Underperform to Market Perform. $37 price target. Better credit performance could lower near-term risk. Big Lots ( BIG) upgraded at Pali from Neutral to Buy. $31 price target. Merchandising is improving, which should drive earnings higher. Compania Buenaventura ( BVN) downgraded at Merrill/BofA to Underperform from Neutral after stock's recent rally. 2009 and 2010 EPS estimates set at $2.07 and $2.77, respectively. $38 price target. Cogent ( CCOI) initiated at Merrill/BofA with a Neutral rating and $13 price target. Constructive view of CCOI's competitive positioning and free cash flow generation, said Merrill/BofA. 2009 and 2010 EPS estimates set at -$0.41 and $0.00, respectively. Carefusion ( CFN) rated new Market Perform at Leerink. Spin-off should help the company, but the stock is already trading at 18 times 2010 expected earnings. Amdocs ( DOX) downgraded at UBS. Rating lowered to Neutral from Buy. Maintains $27 price target. Maintains 2009 EPS estimates of $1.54. Halliburton ( HAL) numbers increased at Goldman to $35. Estimates also boosted, to reflect better international growth. Neutral rating. Halliburton ( HAL) upgraded at Natixis to Buy. $38 price target. Estimates also raised, to reflect a modest business recovery. Southwest Airlines ( LUV) downgraded at JP Morgan. Rating lowered to Underweight from Neutral. Price target lowered to $6.50 from $11.50. 2009 EPS estimates lowered to $0.10 from $0.15.