MOST NOTEWORTHY: Chipotle Mexican Grill, Micrus Endovascular and Acorda Therapeutics were today's noteworthy initiations:

• Jefferies expects the quality gap between Chipotle Mexican Grill (NYSE: CMG) and its peers will become more apparent in a weakening consumer environment. The firm started shares with a Buy rating and $110 target.
  
• Micrus Endovascular (NASDAQ: MEND) was initiated with an Outperform rating and $20 target at Barrington, citing the company's strong product line, improving salesforce, leading market share position and their expectation for continued strong transition from clipping to coiling.
  
• Acorda Therapeutics (NASDAQ: ACOR) was assumed with an Overweight rating at JP Morgan, as they believe the company's Fampridine-SR for multiple sclerosis is a $500M + opportunity

OTHER INITIATIONS:

• Stanford initiated Mariner Energy (NYSE: ME) with a Buy rating and $35 target.
  
• Deutsche Bank assumed Liberty Entertainment (NASDAQ: LMDIA) with a Buy rating and $29 target.
  
• EnerNoc (NASDAQ: ENOC) was initiated with a Neutral rating at Broadpoint.

MOST NOTEWORTHY: Air France, BHP Billiton, AstraZeneca, Broadcom and Savvis were today's noteworthy downgrades:

• Goldman removed shares of Air France (NYSE: AKH) from its Conviction Buy List due to the increase in the price of fuel and the possibility of an economic slowdown.
  
• Goldman downgraded BHP Billiton (NYSE: BHP) to Neutral from Buy and removed the stock from its Pan-Europe Buy List due to valuation.
  
• Merrill Lynch downgraded shares of AstraZeneca (NYSE: AZN) to Sell from Neutral to reflect increased competition from generic-drug makers, a poor pipeline and slow earnings growth.
  
• Wachovia downgraded shares of Broadcom Corporation (NASDAQ: BRCM) to Hold from Buy to reflect valuation and the company's lower than expected Q3 results. Shares were also lowered to Hold from Buy at Deutsche Bank.
  
• Stanford lowered Savvis (NASDAQ: SVVS) to Hold from Buy and notes that the company's Q3 results and Q4 revenue guidance brings the company's 2007 revenue outlook $15M below the consensus, and advises investors to remain on the sidelines. The firm believes the company's strategy is sound, but that its execution has been slow.

OTHER DOWNGRADES:

• Blockbuster (NYSE: BBI) and Akzo Nobel (OTC: AKZOY) were downgraded to Neutral from Overweight at JP Morgan.
  
• Friedman Billings downgraded the E&P sector, including Brigham Exploration Company (NASDAQ: BEXP), Mariner Energy (NYSE: ME) and Nobel Energy (NYSE: NBL) to Market Perform from Outperform.
  
• Baird downgraded Plantronics (NYSE: PLT) to Neutral from Outperform.
  
• Goldman downgraded Boston Scientific (NYSE: BSX) to Neutral from Buy.