CHANGE IN RATINGS

Alberto-Culver ( ACV - Get Report) downgraded at JP Morgan: ACV was downgraded from Overweight to Neutral, JP Morgan said. Stock looks fully valued, given the terms of the breakup. ACV could also come under selling pressure, as it will likely be taken out of the S&P 500.

Ameren ( AEE - Get Report) downgraded at Citigroup: AEE was downgraded from Buy to Hold, Citigroup said. $55.50 price target. Regulatory uncertainty is hanging over earnings visibility and the stock's performance.

AstraZeneca ( AZN - Get Report) downgraded at Bear: AZN was downgraded to Peer Perform, Bear Stearns said. Company posted solid earnings, but quality was poor. NXY-059 failure leaves AZN with just four Phase III products.

Dreamworks ( DWA) upgraded at Merrill: DWA was upgraded from Neutral to Buy, Merrill Lynch said. $31 price target. Stock should recover in the near term, ahead of the new Shrek film. Rest of pipeline also looks good, and the secondary overhang has been lifted.

Enbridge ( ENB - Get Report) upgraded at Credit Suisse: Credit Suisse said it upgrading ENB to Outperform from Neutral based on long-term organic growth. Raised target price to $40 from $32.

Advanced Medical Optics ( EYE - Get Report) upgraded at Citigroup: EYE was upgraded from Hold to Buy, Citigroup said. Stock has already pulled back enough to reflect the recent earnings guidance cut. $48 price target.

Advanced Medical Optics ( EYE - Get Report) estimates cut at Prudential:Prudential said it is cutting its 2007 estimates on EYE by 19 cents to $2.30 a share due to lowered guidance. Maintained Neutral Weight rating.

First Marblehead ( FMD) downgraded at JP Morgan: FMD was downgraded from Overweight to Neutral, JP Morgan said. Lingering concerns could hang over the stock, now that it's already made a large run.

GlaxoSmithKline ( GSK - Get Report) downgraded at Merrill: GSK was downgraded from Buy to Neutral, Merrill Lynch said. Estimates also cut, to reflect slower growth in Advair and Avandia. Timeline of the clinical pipeline has been pushed out.

Gymboree downgraded at Friedman, Billings: GYMB was downgraded from Outperform to Market Perform, Friedman, Billings Ramsey said. Valuation call, as year-over-year growth comparisons will be difficult in the near term.

Hudson City Bancorp ( HCBK) downgraded at Merrill: HCBK was downgraded from Buy to Neutral, Merrill Lynch said. Difficult yield curve environment could cut further into book value. 20% annual earnings growth remains possible.

IGT ( IGT - Get Report) upgraded at Morgan Stanley: Morgan Stanley upgrades IGT from equalweight to overweight and raises its price target from $39 to $55, based on the company's opportunities for international expansion.

Invitrogen downgraded at Deutsche: IVGN was downgraded from Buy to Hold, Deutsche Bank said. $59 price target. Company losing market share in two key markets, and is losing credibility with investors.

Invitrogen downgraded at Citigroup: IVGN was downgraded to Hold, Citigroup said. Company reported a poor quarter, and guided to less margin growth for 2007. Would be a buyer in the low- to mid-$50's. $68 price target.

Lyondell Chemical downgraded at JP Morgan: LYO was downgraded from Overweight to Neutral, JP Morgan said. Stock now seems to be pricing in accretive purchase of the LCR refinery from this summer. Estimates cut, to reflect narrower ethylene margins.

Nektar Therapeutics ( NKTR - Get Report) downgraded at Morgan Stanley: Morgan Stanley downgrades Nektar Therapeutics to underweight from equalweight, on a reduction in the company's peak sales forecast for Exubera.

Red Hat downgraded at Citigroup: RHAT was downgraded from Buy to Sell, Citigroup said. ORCL's entry into the space really hurts the company's business. $13.50 price target.

Red Hat target price slashed at UBS: UBS said it lowering its target price on RHAT to $16 from $22 following Oracle's plan to offer support for Linux distribution at reduced prices. Maintained Neutral rating.

Schwab ( SCHW) upgraded at Prudential:Prudential said it is upgrading SCHW to an Overweight rating as company has leverage in model and superior asset growth. Target raised to $23.

Tim Hortons ( THI) upgraded at Goldman Sachs: Goldman said it is upgrading THI to Buy from Neutral due to increasing sales strength in Q4, reduction in expenses, and higher revenues. Price target at $34.

T Rowe Price ( TROW) upgraded at AG Edwards: TROW was upgraded from Hold to Buy, AG Edwards said. Recent pullback created a buying opportunity. Company continues to post better organic growth than its peers. $51 price target.

T Rowe Price ( TROW) downgraded at Friedman, Billings: TROW was downgraded to Market Perform, Friedman, Billings said. $47.50 price target. Company generating solid organic growth, but valuation appears full.

Yum Brands ( YUM) downgraded at Goldman Sachs: Goldman said it is downgrading YUM to Neutral from Buy based on valuation. See reduced upside following strong recent share performance. Price target at $62.

STOCK COMMENTS / EPS CHANGES

Akamai ( AKAM - Get Report) price target raised at Jefferies: Jefferies said it is increasing its target on AKAM to $60 from $59 after company reported better than expected Q3 results. See continuing growth fueled by increased ARPU and margin expansion. Reiterated Buy rating.

Airgas ( ARG) outlook raised at UBS: UBS said it raising its 2007 EPS estimates on ARG by 5 cents to $1.95 following solid F2Q results. Raised target price to $43 from $42.

Comcast ( CMCSA - Get Report) estimates raised at Prudential: Prudential said it is raising its 2006 estimates on CMCSA by 10 cents to 88 cents a share due to better-than-expected results. Maintained Overweight rating, target raised to $48.

Comcast ( CMCSA - Get Report) target price raised at UBS: UBS said it raising its target price on CMCSA to $47 from $42 following strong 3Q results. Maintained Buy rating.

Sun Microsystems ( SUNW) estimates raised at Prudential: Prudential said it is raising its 2007 estimates on SUNW to a loss of a penny a share due to EPS upside. Maintained Underweight rating.

Sun Microsystems ( SUNW) estimates raised at Credit Suisse: Credit Suisse said it raising its 2007 EPS estimates on SUNW to $0.03 from a loss of $0.02 based on strong server growth. Maintained Underperform rating.

MEMC Electronic ( WFR) outlook raised at UBS: UBS said it raising its 2006 EPS estimates on WFR by 6 cents to $1.96 following solid 3Q results. Raised target price to $60 from $55.