Top Analyst Upgrades and Downgrades (ATVI, CELG, COST, EA, ECPG, HST, LEAP, MAR, PCS, PAL, SI, SPLS, TTWO, TCBI, TXN, ZNGA)

These are some of the top analyst upgrades, downgrades and initiations we have seen from Wall St. research calls this Thursday.

Activision Blizzard Inc. (NASDAQ: ATVI) started as Outperform with $16 target at Credit Suisse.

Celgene Corp. (NASDAQ: CELG) cut to Neutral at Piper Jaffray.

Costco Wholesale Corp. (NASDAQ: COST) reiterated Buy and raised target to $113 at Argus.

Electronic Arts Inc. (NASDAQ: EA) started as Neutral at Credit Suisse.

Encore Capital Group Inc. (NASDAQ: ECPG) named value stock of the day at Zacks.

Host Hotels & Resorts Inc. (NYSE: HST) cut to Neutral at Goldman Sachs.

Leap Wireless International Inc. (NASDAQ: LEAP) raised to Outperform at Oppenheimer.

Marriott International Inc. (NYSE: MAR) cut to Neutral at Goldman Sachs.

MetroPCS Communications Inc. (NYSE: PCS) cut to Underperform at Oppenheimer.

North American Palladium Ltd. (NYSEMKT: PAL) raised to Outperform at Credit Suisse.

Siemens A.G. (NYSE: SI) cut to Hold at Deutsche Bank.

Staples Inc. (NASDAQ: SPLS) named Bear of the Day at Zacks.

Take-Two Interactive Software Inc. (NASDAQ: TTWO) started as Neutral at Credit Suisse.

Texas Capital Bancshares Inc. (NASDAQ: TCBI) named as Bull of the Day at Zacks.

Texas Instruments Inc. (NASDAQ: TXN) cut to Neutral at Credit Suisse.

Zynga Inc (NASDAQ: ZNGA) started as Underperform with $3 target at Credit Suisse.

JON C. OGG