NEW YORK ( TheStreet) -- CHANGE IN RATINGSAGCO ( AGCO) was downgraded to neutral at UBS. Sharp corn prices declines will impact shares in the growing season (June - August), UBS said. Yamana Gold ( AUY) was upgraded at Cowen Securities to buy from hold. Production should significantly ramp in 2013, with new projects coming online. Cracker Barrel ( CBRL) was downgraded at Miller Tabak to hold from buy. Valuation call, as Brinker International ( EAT) appears more attractive at current levels, Miller Tabak said. Chesapeake Energy ( CHK) was downgraded at Sterne Agee to underperform from neutral. $20 price target. Current hedges dampen exposure to resurgent natural gas prices, Sterne Agee said. Deere ( DE) was downgraded at UBS to neutral. Corn prices are expected to decline sharply, and given the close correlation between DE shares and corn prices, this will drive significant underperformance, UBS said. Electronic Arts ( EA) was downgraded at Needham to hold from buy. Company continues to struggle and still needs to find a new CEO, Needham said. eBay ( EBAY) was upgraded to buy from hold at Cantor Fitzgerald. Stock is attractive, following a 13% pullback, Cantor Fitzgerald said. International Paper ( IP) was initiated with a hold rating at Keybanc. Stock is already pricing in expected industry price increases, Keybanc said. Juniper Networks ( JNPR) was downgraded at Goldman Sachs to sell from neutral. The company will see market share negatively affected by competition, Goldman said. Earnings estimates are reduced through 2015 and the price target goes to $17. Kohl's ( KSS) was downgraded at Morgan Stanley to underweight. The macro environment poses a threat to consensus estimates and valuation is at a premium, Morgan Stanley said. Estimates were reduced and price target is $42. Lululemon ( LULU) was downgraded at Sterne Agee to neutral from buy. Quality control problem in Asia where Luon pants are produced, Sterne Agee said. NextEra Energy ( NEE) was upgraded at KeyBanc to buy from hold. $80 price target. Solid story trades at meaningful discount, KeyBanc said. OGE Energy ( OGE) was downgraded at Argus Research to hold from buy. Valuation call, as the stock is up 35% over the past year, Argus said.