MOST NOTEWORTHY: Seagate, Nortel Networks and Ann Taylor were today's noteworthy downgrades:

• Thomas Weisel downgraded Seagate (NYSE: STX) to Market Weight from Overweight as they believe the company's growth will be more muted given high existing market share and overall industry growth.
  
• Baird downgraded Nortel (NYSE: NT) to Neutral from Outperform citing checks that indicate deteriorating US Enterprise sales in the last few weeks of Q1. The firm now expects companies to guide flat QoQ instead of up and to make cautious 2H08 comments.
  
• Ann Taylor (NYSE: ANN) was cut to Neutral from Buy at Piper to reflect concerns over the LOFT division as well as consumer spending.

OTHER DOWNGRADES:

• Citigroup lowered TJX Cos (NYSE: TJX) to Hold from Buy.
  
• WestLB downgraded to Hold from Add Novartis (NYSE: NVS).
  
• Hartford Financial (NYSE: HIG) was downgraded to Neutral from Buy at UBS.

MOST NOTEWORTHY: Cott Corp, Hartford Financial, Allstate and Valero Energy were today's noteworthy upgrades:

• Lehman upgraded Cott Corp (NYSE: COT) to Equal Weight from Underweight citing recent management changes, a focus on CSD business, and new product discipline.
  
• Bernstein believes the entire non-life insurance group is oversold and that it is time to buy; the firm upgraded Hartford Financial (NYSE: HIG) and Allstate (NYSE: ALL) to Outperform from Market Perform.
  
• Valero Energy (NYSE: VLO) was raised to Buy from Hold at Deutsche Bank on valuation with the stock trading at a -30% discount to NAV while the asset market for U.S. refineries is strong.

OTHER UPGRADES:

• Goldman added Cisco (NASDAQ: CSCO) to its Conviction Buy List.
  
• RBC Capital upgraded BJ Services (NYSE: BJS), Halliburton (NYSE: HAL) and Patterson-UTI Energy (NASDAQ: PTEN) to Outperform from Sector Perform.
  
• Friedman Billings upgraded the Semiconductor Capital Equipment sector to Overweight from Market Weight.

How vulnerable is your mutual fund to the ongoing mortgage meltdown? In this series, BloggingStocks contributor Lita Epstein, author of more than 20 books including Trading for Dummies and The Complete Idiot's Guide to Improving Your Credit Score, digs into mutual funds' holdings looking for securities with exposure to the currently shaky credit markets.

After reviewing funds from Bank of America, JPMorgan, and Fidelity, companies that have been mentioned in some of the SIV bailout stories, I looked to see if other bond mutual funds also had significant exposure to the credit markets tied to this mortgage and asset-backed securities mess. While I can't guarantee that I located all the ones with significant exposure to this mess, here are some key players:

Eaton Vance Low Duration A has the riskiest position by far of all the ones I look at this morning. As of 04/30/07, this fund held 79.93% of its assets in mortgage pass-through securities. More than 75% of its holdings are in bonds rated BB and B. Its yield of 5.5% certainly doesn't justify this risk. If you are holding this fund, you could find a safer bet with similar yields.

As of 9/30/2007, Credit Suisse Short Duration A held 15.43% of its assets in mortgage pass-through securities, 13.86% in collateralized mortgage obligations, and 12.82% in asset-back securities. That's slightly more than 40% of its portfolio in the type of credit markets now showing signs of trouble.

MOST NOTEWORTHY: Today's noteworthy upgrades included Lockheed Martin (LMT), Raytheon (RTN), Hartford Financial (HIG), Seagate Technology (STX) and CommScope (CTV):

• JP Morgan upgraded two defense stocks today: Lockheed Martin (NYSE: LMT) was upgraded to Neutral from Underweight on valuation;

• Raytheon (NYSE: RTN) was raised to Overweight from Neutral, with expectations for the company to post above average organic growth driven by strong bookings. The firm also raised Raytheon's 2008 EPS estimate to $3.80 from $3.60, well above the consensus estimate.

• AG Edwards believes Hartford Financial's (NYSE: HIG) recent weakness has created a buying opportunity and upgraded shares to Buy from Hold.

• Seagate (NYSE: STX) was upgraded to Buy from Hold at Brean Murray as checks indicate a healthy seasonal uptick in demand for drives and PCs in 2H07.

• CommScope (NYSE: CTV) was Upgraded to Outperform from Market Perform at Morgan Keegan based on higher 2007 and 2008 expectations along with accretion from the Andrew acquisition...

OTHER UPGRADES:

• BMC Software (NYSE: BMC) was upgraded to Neutral from Underperform at Credit Suisse.

• Friedman Billings raised Kimco Realty (NYSE: KIM) to Outperform from Market Perform.

• Merck (NYSE: MRK) was upgraded to Buy from Hold at AG Edwards.

• Int'l Speedway (NASDAQ: ISCA) was upgraded to Buy from Hold at Matrix USA.

• JP Morgan added Cognizant Technology Solutions (NASDAQ: CTSH) to its JP Morgan Focus List.

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