NEW YORK (TheStreet) -- RATINGS CHANGES

Covanta Holding

(CVA) - Get Report

was downgraded at Barclays to equal-weight from overweight. Valuation has been fully realized after 37% year-to-date gain, Barclays said.

Cypress Semiconductor(CY) - Get Report was upgraded at Topeka Capital to buy from hold. Twelve-month price target is $13. Spansion (CODE) purchase should have attractive cost synergies, Topeka said.

Mellanox(MLNX) - Get Report was upgraded at Barclays to overweight from equal-weight. Tailwinds over the next 18 to 24 months include strength in the HPC industry, an upcoming server refresh cycle, data center and storage spending trends, strength in the 40G market and the eventual move to 100G, Barclays said. Twelve-month price target was raised to $57 from $50.

Nokia Oyj(NOK) - Get Report was upgraded to buy at TheStreet Ratings. You can view the full analysis from the report here: NOK Ratings Report.

Prosperity Bancshares(PB) - Get Report was upgraded at FIG to outperform from market perform. Twelve-month price target is $65. Stock has pulled back to an attractive level, FIG said.

Priceline.com (PCLN) was downgraded at FBR Capital Markets to market perform from outperform. Twelve-month price target is $1,225. Guidance suggests that growth is decelerating, FBR Capital Markets said.

PerkinElmer(PKI) - Get Report was downgraded at Goldman Sachs to neutral from buy. Company was also cut from the Conviction list. Valuation call, based on a 12-month price target of $47, Goldman Sachs said.

Sanchez Energy(SN) - Get Report was downgraded to sell at TheStreet Ratings. You can view the full analysis from the report here: SN Ratings Report.

Theravance (THRX) was downgraded at Leerink Partners to market perform from outperform. Twelve-month price target is $17. Survey suggests limited upside potential for Breo and Anoro, Leerink Partners said.

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This article was written by a staff member of TheStreet.