Harley-Davidson ( HOG)upgraded at JP Morgan from Neutral to Overweight, JP Morgan said. $56 price target. Company can continue to expand operating margins. Intuitive Surgical ( ISRG) upgraded at BofA to Buy from Neutral, Bank of America Merrill Lynch said. $620 price target. Da vinvi robot should play a significant role in US general surgery over time. Janus Capital Group ( JNS) downgraded at JP Morgan to Underweight from Neutral, JP Morgan said. $9.50 price target. Valuation has outpaced fundamentals. Key ( KEY) downgraded at Citigroup to Neutral from Buy, Citigroup said. $9 price target. Approaching peak liability repricing leverage. Alliant Energy ( LNT) upgraded at Wunderlich from Hold to Buy, Wunderlch said. $50 price target. Earnings growth can accelerate, given higher rates in Iowa. Marvell Technology ( MRVL) downgraded at FBR from Outperform to Market Perform, FBR Capital Markets said. $9.50 price target. Company can continue to lose market share in cellular. Marvell Technology Group downgraded at Oppenheimer to Hold from Buy, Jefferies said. $9 price target. Quarter miss and CFO departure. Hold rating. Marvell Technology downgraded at Craig-Hallum from Buy to Hold, Craig-Hallum said. $10 price target. Company cut guidance and its CFO stepped down. Marvell Technology downgraded at Lazard from Buy to Neutral, Lazard said. CFO is leaving and the company cut its sales guidance. Northrop Grumman ( NOC) downgraded at Oppenheimer to Perform from Outperform, Oppenheimer said. Valuation looks full. Nvidia ( NVDA) downgraded at FBR from Outperform to Market Perform, FBR Capital Markets said. $14 price target. Company is leveraged to lower PC demand and lacks near-term catalysts. Sandisk ( SNDK) upgraded at Piper to Overweight, Piper Jaffray said. $53 price target. Company should benefit from changes in the NAND market. Sonoco Products ( SON) downgraded at JP Morgan from Overweight to Neutral, JP Morgan said. Valuation call, based on a $37 price target. T. Row Price ( TROW) upgraded at JP Morgan to Overweight from Neutral, JP Morgan said. $77 price target. Potential for retail re-engagement. Textron ( TXT) upgraded at JP Morgan from Neutral to Overweight, JP Morgan said. New analyst has a $29 price target.