Analyst upgrades, downgrades and initiations: BJ, CX, MRK, VLKAY, WMT ...

Analyst upgrades:

Deutsche Bank upgraded Cemex (NYSE: CX) to Buy from Hold on decreased dilution risk following the company's successful refinancing and raised its target on shares to $15 from $11.20.
Rochdale upgraded Wal-Mart (NYSE: WMT) to Buy from Neutral and raised its target to $65. The firm is positive on Wal-Mart's defensive characteristics, cyclical upside, and competitive position.
JPMorgan upgraded Gartner Group (NYSE: IT) to Overweight from Neutral to reflect stabilization in IT industry spending and the stock's attractive valuation. The firm has a $23 price target on the stock.
Cavium Networks (NASDAQ: CAVM) was upgraded to Overweight from Equal Weight at Barclays.
Borg-Warner (NYSE: BWA) was upgraded to Buy from Neutral at BofA/Merrill.
Nanometrics (NASDAQ: NANO) was upgraded to Outperform from Perform at Oppenheimer.

Analyst downgrades:

JPMorgan downgraded BJ's Wholesale (NYSE: BJ) to Neutral from Overweight. The firm believes food disinflation poses risk to the company's second half of 2009 SSS outlook and has a $34 target on the stock.
Wells Fargo downgraded Public Storage (NYSE: PSA) to Market Perform from Outperform. The firm downgraded the stock on valuation, and because it expects same-store NOI growth to remain soft into 2010.
Oppenheimer downgraded REIT shares citing the recent strength in the group. BioMed Realty Trust (NYSE: BMR) and Boston Properties (NYSE: BXP) were cut to Outperform from Perform, while Washington REIT (NYSE: WRE) was lowered to Underperform from Perform.
Volkswagen (OTC: VLKAY) was downgraded to Neutral from Overweight at HSBC.
Boardwalk Pipeline (NYSE: BWP) was downgraded to Hold from Buy at Deutsche Bank.

Analyst initiations:

Deutsche Bank initiated STEC (NASDAQ: STEC) with a Buy rating and $45 target. The firm believes the enterprise storage SSD market can grow significantly over the next couple of years and that STEC is attractively valued at current levels.
Oppenheimer expects Ariad's (NASDAQ: ARIA) lead cancer drug, Ridaforolimus, will receive approval for sarcoma and estimates peak sales at $350M. Shares were started with an Outperform rating and $4 target.
Oppenheimer also initiated American Physicians (NASDAQ: AMPH) with an Outperform rating. The firm believes that the company is poised to deliver attractive returns, since its book value increased by more than 10% last year.
Merck (NYSE: MRK) was reinstated with a Buy rating and $34 target at BofA/Merrill.
EnerNOC (NASDAQ: ENOC) was initiated with an Overweight rating and $32.50 target at JPMorgan.
DigitalGlobe (NYSE: DGI) was initiated with an Overweight rating and $25 target at Morgan Stanley