NEW YORK ( TheStreet) -- CHANGE IN RATINGSAmgen ( AMGN) downgraded at Oppenheimer to Perform from Outperform, Oppenheimer said. Few upside drivers remaining in 2012. Arris ( ARRS) upgraded at Collins Stewart from Neutral to Buy, Collins Stewart said. $15 price target. Moxi should still achieve full-year sales targets. Arris Group downgraded to hold at TheStreet Ratings. Atmel ( ATML) downgraded to hold at TheStreet Ratings. Big Lots ( BIG) rated new Neutral at JP Morgan. $48 price target. Company is turning sales around buy management has a choppy track record. Celanese Corporation ( CE) upgraded at Jefferies to Buy from Hold, Jefferies said. $65 price target. Ethanol and AO+ should buoy shares. CIT Group ( CIT) upgraded at Morgan Stanley from Equal-weight to Overweight, Morgan Stanley said. $48 price target. Company is moving back toward an investment-grade credit rating. Compass Minerals ( CMP) downgraded at JP Morgan from Neutral to Underweight, JP Morgan said. $66 price target. Customer inventories are likely high heading into the new year. Cisco Systems ( CSCO) downgraded at ISI from Buy to Neutral, ISI Group said. Valuation call, based on a $22 price target. DuPont Fabros ( DFT) downgraded at Jefferies to Hold from Buy, Jefferies said. $24 price target. Too much uncertainty around lease up. Dollar Tree ( DLTR) rated new Overweight at JP Morgan. $100 price target. Company can generate sustainable 20% annual earnings growth. Ingram Micro ( IM) downgraded at Needham from Buy to Hold, Needham said. Valuation call, based on a $20 price target. iRobot ( IRBT) downgraded at JP Morgan to Underweight, JP Morgan said. $30 price target. Company slashed its guidance. Joy Global ( JOY) downgraded at Jefferies to Hold from Buy, Jefferies said. $90 price target. Shares have met price target. 3M ( MMM) downgraded at Deutsche from Buy to Hold, Deutsche Bank said. Valuation call, based on a $95 price target. Solutia ( SOA) downgraded at Jefferies to Hold from Buy, Jefferies said. $28.50 price target. Reflecting the prospect of Eastman's acquisition of Solutia for $22 in cash and 0.12 shares. Thoratec ( THOR) upgraded at Piper to Overweight, Piper Jaffray said. $37 price target. Stock is already factoring in higher potential competition. TripAdvisor ( TRIP) downgraded at Benchmark from Buy to Hold, Benchmark said. $31 price target. Growth and margin expansion may still be a year away.