U.S. stock futures are lower Wednesday morning as investors await the latest ADP jobs data. Futures on the Dow Jones Industrial Average fell 59 points to 11,560 and S&P 500 futures dropped 8.10 points to 1,257.20. Futures for the Nasdaq 100 index fell 13 points at 2,232.50.

U.S. stock markets closed mixed yesterday, with the Dow gaining 0.18%, the Nasdaq Composite losing 0.38% and S&P 500 dropping 0.13%.

MOST NOTEWORTHY: Trident Microsystems, Comcast, Level 3 Communications, Ambac Financial and MBIA Inc were today's noteworthy downgrades:

• Jefferies downgraded shares of Trident Microsystems Inc (NASDAQ: TRID) to Hold from Buy and lowered their target to $9 from $20 following the company's mixed quarter as they expect TRID to lose share in the TV market and face increasing price pressure. Shares were also downgraded to Hold from Buy at Deutsche Bank. Oppenheimer lowered Trident to Neutral from Buy, citing disappointing December guidance, delay in TV ramp, and expectations that 2008 will be a peak year for TV chip ramp revenues.
• CIBC downgraded shares of Comcast Corporation (NASDAQ: CMCSA) to Sector Performer from Outperformer following the weak Q3 results to reflect increasing competition in telco video, slower broadband growth and the weakening economy.
• JP Morgan downgraded Level 3 Communications Inc (NASDAQ: LVLT) to Neutral from Outperform following disappointing Q3 results and guidance.
• Friedman Billings downgraded shares of Ambac Financial Group Inc (NYSE: ABK) and MBIA Inc (NYSE: MBI) to Market Perform from Outperform citing lack of near-term catalysts and uncertainty surrounding the credit markets.

OTHER DOWNGRADES:

• Banc of America lowered its rating on Eli Lilly and Company (NYSE: LLY) to Neutral from Buy.
• WestLB downgraded GlaxoSmithKline PLC (NYSE: GSK) to Sell from Add.
• Societe Generale downgraded France Telecom (NYSE: FTE) to Hold from Buy.
• Franklin Resources Inc (NYSE: BEN) was downgraded to Market Perform from Outperform at Friedman Billings and at Keefe Bruyette.

MOST NOTEWORTHY: JDS Uniphase (JDSU-old, JDSUD), Western Digital (WDC) and MGM Mirage (MGM) top today's list of upgrades.

• JDS Uniphase Corp. (NASDAQ:JDSUD) was upgraded to Strong Buy from Buy at Needham. They believe the worst is over for JDSU and see upside to near-term estimates after the company's profitable first-quarter results. JDS Uniphase was also upgraded by Deutsche Bank to Buy from Hold, citing valuation and expectations of improved profitability.
• Western Digital Corp. (NYSE:WDC) was upgraded to Outperform from Market Perform at Raymond James following their strong earnings report.
• MGM Mirage (NYSE:MGM) was upgraded to Buy from Hold at KeyBank/McDonald based on valuation and fundamentals.

OTHER UPGRADES:

• Sina Corp (NASDAQ:SINA) was upgraded to Buy from Hold at Deutsche Bank. The firm cited Sina's strong results and a positive 2007 outlook for the upgrade. Citigroup also upgraded Sina Corp to Buy from Hold.
• DA Davidson upgraded Trident Microsystems, Inc. (NASDAQ:TRID) to Buy from Neutral on valuation.
• Finally, JP Morgan upgraded Unilever N.V. (NYSE:UN) to Neutral from Underweight. The firm expects positive news flow and possible upside surprises over the next six to nine months driven by margin expansion and cost stabilization.

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