NEW YORK ( TheStreet) -- CHANGE IN RATINGSACE Limited ( ACE) upgraded at Citi to Buy and added to Top Picks Live. Superior reserve/capacity profile and upside potential with A&H business. Price target raised to $64. Ametek ( AME) upgraded at Baird from Neutral to Outperform. Company reported a strong quarter. $49 price target. Ashland ( ASH) upgraded at Longbow from Neutral to Buy. Estimates also boosted, given price increases. $75 price target. Bill Barrett Corp ( BBG) upgraded at Barclays to Overweight from Equal Weight on valuation. Perception that the company's Rockies project could be pressured in current price environment. Price target increased to $43 from $38. Dell ( DELL) downgraded at UBS from Buy to Neutral. Valuation call, as the stock is up 25% in the past two months. $17.50 price target. Domino's Pizza ( DPZ) downgraded at Citi to Hold from Buy on valuation and high expectations. Price target raised by a dollar to $19.50. 2010 and 2011 EPS estimates lifted to $1.30 and $1.41, respectively. Davita ( DVA) downgraded at Jefferies from Buy to Hold. $69 price target. Multiple potential negative catalysts lie ahead. Ford ( F) downgraded at Credit Suisse to Underperform from Neutral. Profit levels have red-lined, time to down-shift. Maintain $10 price target. Ford ( F) target, estimates raised at Barclays. F price target inched higher to $13 from $12 on solid 1Q10 beat. 2010 and 2011 EPS estimates lifted to $1.57 and $1.85, respectively. Equal Weight rating. Ford ( F) estimates increased at UBS through 2011. Company is seeing better results for credit and in Europe. Buy rating and $16 price target. Forest Oil ( FST) downgraded at Barclays to Equal Weight from Overweight based on recent share performance. 3M ( MMM) estimates, target upped at UBS. MMM estimates were boosted through 2011. Company is seeing better organic growth. Buy rating and new $110 price target. 3M ( MMM) upgraded at Barclays to Overweight from Equal Weight on better than expected 1Q10 results. Price target jumped to $105 from $90. Estimates raised through 2012.