Analyst Upgrades

• Marriott (MAR) to outperform from market perform at Wells Fargo.
• Quest Diagnostics (DGX) and Owens-Illinois (OI) to outperform from neutral at Credit Suisse.
• FirstMerit (FMER) to outperform from perform at Oppenheimer.
• Safeway (SWY) to hold from sell at Citigroup.
• Babcock & Wilcox (BWC) to buy from neutral, as well as Jacobs Engineering (JEC) and W. R. Berkley (WRB) to neutral from sell, at Goldman.
• Pioneer Natural (PXD) to overweight from equal weight at Barclays.
• Teekay Tankers (TNK) to buy from underperform at BofA/Merrill.

Analyst Upgrades

• Applied Materials (AMAT) to overweight from neutral at Piper Jaffray.
• Air Products (APD) to buy from hold at Citigroup.
• Youku.com (YOKU) and Pinnacle West (PNW) to buy from neutral at Goldman.
• Stryker (SYK) and Zimmer (ZMH) to buy from neutral at UBS.
• Zions Bancorp (ZION) to outperform from neutral at Macquarie.
• Alnylam (ALNY) to buy from hold at Needham.
• AK Steel (AKS) to buy from hold at KeyBanc.

Analyst Upgrades

• Air Products (APD) to buy from hold at Deutsche Bank.
• Zimmer (ZMH) to outperform from neutral at RW Baird.
• SunPower (SPWRA) to buy from hold at Jefferies.
• Brocade (BRCD) to buy from hold at Wunderlich and at ThinkEquity.
• Duke Energy (DUK) to neutral from underperform at BofA/Merrill.
• NewStar Financial (NEWS) to outperform from market perform at Keefe Bruyette.
• Hormel Foods (HRL) to hold from sell at Soleil.
• Inspire Pharma (ISPH) to hold from sell at Duncan-Williams.
• Alnylam (ALNY) to buy from neutral at Roth Capital.
• Weight Watchers (WTW) to equal weight from underweight at Morgan Stanley.
• Raytheon (RTN) and Toreador Resources (TRGL) to outperform from sector perform at RBC Capital.

Analyst Upgrades

• JPMorgan upgraded Vivus (VVUS) to overweight from neutral.
• Citigroup upgraded Corn Products (CPO) to buy from hold.
• Maxim Integrated (MXIM) was upgraded to outperform from market perform at FBR Capital.
• Cardinal Health (CAH) was upgraded to outperform from neutral at RW Baird.
• Citigroup upgraded Monster Worldwide (MWW) and EchoStar (SATS) to buy from hold, as well as Las Vegas Sands (LVS) to buy from sell.
• BMO Capital upgraded Potash (POT) and Barrick Gold (ABX) to outperform from market perform.

Zimmer Holdings (ZMH) was the only S&P 500 stock that did not lose ground Tuesday -- a day when the S&P 500 itself fell more than 3%.

So what kept Zimmer afloat while everything else around it was sinking?

Goldman Sachs did upgrade Zimmer from a neutral rating to a buy rating, but it's hard to believe that upgrade alone was enough to enable the stock to hold its ground. However, that upgrade may be a symptom of growing bullishness behind Zimmer.

Analyst upgrades

• UBS upgraded CF Industries (CF) to neutral from sell. The firm cites valuation for the upgrade. In addition, UBS raised its price target on shares to $84 from $81.
• Baird upgraded Johnson Controls (JCI) to outperform from neutral and raised its price target to $42 from $33. The upgrade was based on improving margins, China growth, and upside from a cyclical recovery.
• Barrington upgraded G&K Services (GKSR) to outperform from market perform ahead of the company's Q3 results to reflect optimism regarding the company's operational turnaround. The firm set a $35 price target for shares.
• LaSalle Hotel (LHO) was upgraded to top pick from outperform at RBC Capital.
• Zimmer (ZMH) was upgraded to overweight from neutral at JPMorgan.
• Thermo Fisher (TMO) was upgraded to buy from hold at Jefferies.

Analyst upgrades:

• Citigroup upgraded Advanced Micro (NYSE: AMD) to Buy from Hold and raised its target to $5.50 from $4.25 citing valuation and expectations for the company's competitive position and gross margins to improve.
• Barclays upgraded American Express (NYSE: AXP) to Overweight from Equal Weight citing long-term earnings growth as the company benefits from declining charge-offs and credit costs. The firm has a $38 target on the stock.
• JPMorgan upgraded Arch Coal (NYSE: ACI) to Overweight from Neutral and raised its target to $22 from $19 citing the FTC approval for the acquisition of Jacobs Ranch mine and valuation.
• Bebe Stores (NASDAQ: BEBE) was upgraded to Overweight from Equal Weight at Stephens.
• Cheesecake Factory (NASDAQ: CAKE) was upgraded to Neutral from Underweight at Piper Jaffray.
• Ashland (NYSE: ASH) was upgraded to Buy from Hold at KeyBanc.

MOST NOTEWORTHY: QLogic (QLGC), Cnet Networks (CNET), Taiwan Semiconductor (TSM), Darden Restaurants (DRI) and Anadys Pharma (ANDS) were today's noteworthy downgrades:

• QLogic (NASDAQ: QLGC) was cut by several firms:
  
• QLogic was cut to Neutral from Outperform and removed from JP Morgan's Focus List due to the lack of catalysts to drive shares higher.
  
• Caris cut shares to Average from Above Average and Pacific
  
• Crest downgraded QLogic to Sector Perform from Outperform as the company's profits decline.

• Citigtroup downgraded CNet Networks (NASDAQ: CNET) to Hold from Buy as they no longer expect material revenue growth acceleration and operating leverage in 2H07; First Albany cut shares to Neutral from Buy.

• HSBC downgraded shares of Taiwan Semiconductor (NYSE: TSM) to Neutral from Overweight to reflect worse than expected pricing pressures.

• Matrix downgraded shares of Darden Restaurants (NYSE: DRI) to Hold from Buy on increasing competition and rising costs.

• Piper cut Anadys Pharma (NASDAQ: ANDS) to Underperform from Outperform following the company's announcement that it has discontinued development of ANA975...

OTHER DOWNGRADES:

• First Albany cut Zimmer Holdings (NYSE: ZMH) to Buy from Strong Buy.

• Bear Stearns downgraded AutoNation (NYSE: AN) to Peer Perform from Outperform.

• Piper Jaffray downgraded Volcom (NASDAQ: VLCM) and Sierra Wireless (NASDAQ: SWIR) to Market Perform from Outperform.

• Bernstein downgraded Coca-Cola Enterprises (NYSE: CCE) to Underperform from Market Perform.

Analyst summaries provided by TheFlyOnTheWall.com (subscription required).

Smith & Nephew plc (NYSE:SNN) announced the acquisition this morning of Swiss company Plus Orthopedics for $889 million in cash. This will solidify Smith & Nephew's position as the number 4 global player. The other three major firms are Stryker Corp. (NYSE:SYK), Zimmer Holdings (NYSE:ZMH), and soon to be acquired Biomet Inc. (NASDAQ:BMET). Biomet is undergoing due diligence by a group of private equity firms led by the Blackstone Group. The transaction is expected to close by October of this year.

The orthopedic sector has the wind at its back. The approval process for an orthopedic device is rigorous, but not as lengthy as the cardiac device sector. The marketplace is global in nature and the demographics are about to enter the sweet spot.

With 78 million U.S. baby boomers alone, and another 80 million-plus baby boomers in the European markets, the aging of this group is ripe for the sector. New hips, knees, elbows and shoulders will see record recipients as each year unfolds. Besides the basic joint-replacement products, the spinal sector is also expected to see massive growth. Minimally invasive surgical procedures are expanding the addressable market as the risk profile for such surgeries is significantly less. The dread of osteoporosis affects nearly 700,000 women in the United States alone.