Today's Upgrades and Downgrades...

These are some of this Thursday’s top analyst upgrades, downgrades, and initiations seen having an impact from Wall Street research calls.

Chevron Corporation (NYSE: CVX) Cut to Underweight at JPMorgan.
Chipotle Mexican Grill, Inc. (NYSE: CMG) Cut to Market Perform at William Blair.
Costco Wholesale Corporation (NASDAQ: COST) Cut to Market Perform at William Blair; Reiterated Outperform at Credit Suisse; Raised target to $90 at Argus.
Deere & Co. (NYSE: DE) Maintained Neutral but cut estimates and target to $87 at Credit Suisse.
Exxon Mobil Corporation (NYSE: XOM) Cut to Underweight at JPMorgan.
Discover Financial Services (NYSE: DFS) named Bull of the Day at Zacks.
Leap Wireless International Inc. (NASDAQ: LEAP) maintained Neutral but target to $4 from $10 at Credit Suisse.
News Corporation (NASDAQ: NWS.A) Removed from the Conviction Buy List at Goldman Sachs.
Newmont Mining Corporation (NYSE: NEM) named Value stock of the day at Zacks.
Oracle Corporation (NASDAQ: ORCL) Reiterated Outperform on Focus List at Credit Suisse.
Polo Ralph Lauren Corp. (NYSE: RL) Raised to Buy at Citigroup.
Polycom Inc. (NASDAQ: PLCM) Raised to Buy at Argus.
PG&E Corporation (NYSE: PCG) Raised to Buy at Citigroup.
Ryanair Holdings plc (NASDAQ: RYAAY) Raised to Outperform at Credit Suisse.
Sony Corporation (NYSE: SNE) Cut to UNderperform at BofA/ML.
Walgreen Co. (NYSE: WAG) Cut to Neutral at BofA/ML.