Up/Downgrades: PTEN, ZMH, REGN, CTCT, KOG, QGEN, UGI, STX, ZNGA, NIHD

Published on Friday, 27 April 2012 08:02 Written by Christian Paolinetti

New York, April 27th (TradersHuddle.com) - Research Calls ahead of the market open.

Patterson-UTI (NASDAQ:PTEN) was downgraded to Underperform from Market Perform at BMO Capital.

Zimmer Holdings (NYSE:ZMH) was upgraded to Outperform from Market Perform at BMO Capital.

Regeneron Pharmaceuticals (NASDAQ:REGN) was downgraded to Market Perform from Outperform at BMO Capital.

Constant Contact (NASDAQ:CTCT) was downgraded to Market Perform from Outperform at William Blair.

Kodiak Oil & Gas (NYSE:KOG) was downgraded to a Neutral from Outperform at Macquarie.

Qiagen (NASDAQ:QGEN) was downgraded to Market Perform from Outperform at Leerink Swann.

UGI Corp. (NYSE:UGI) was upgraded to Outperform from Market Perform at BMO Capital.

Seagate Technologies (NASDAQ:STX) was downgraded to a Neutral from Buy at Bank of America Merrill.

Zynga (NASDAQ:ZNGA) was upgraded to a Neutral from Underperform at Bank of America Merrill.

NII Holdings (NASDAQ:NIHD) was downgraded to Underweight from Neutral at HSBC Securities.