MOST NOTEWORTHY: ComScore, Duke Realty, Nordstrom and Sun Healthcare were among today's noteworthy upgrades:

• ComScore (NASDAQ: SCOR) was upgraded to Outperform from Perform at Oppenheimer to reflect the strong Q1 report and strong customer additions.
  
• Duke Realty (NYSE: DRE) was upgraded to Outperform from Market Perform at Wachovia upgraded based on valuation.
  
• Nordstrom (NYSE: JWN) was upgraded to Outperform from Neutral at Credit Suisse.
  
• Sun Healthcare (NASDAQ: SUNH) was upgraded to Outperform from Market Perform at Friedman Billings based on valuation and notes the Medicare rate cuts will be as drastic as feared.

OTHER UPGRADES:

• MedAssets (NASDAQ: MDAS) was upgraded to Buy from Neutral at Piper, which thinks the company's acquisition of Accuro will strengthen its revenue cycle management offering, and the firm believes the tight credit markets make the company's MedAssets a compelling product in the short-term. In addition, Piper notes that the company has recently had success with large hospital systems.
  
• Jones Apparel (NYSE: JNY) was upgraded to Buy from Neutral at Merrill citing sales expectations for the l.e.i. brand at Wal-Mart (NYSE: WMT) and margin improvements from leaner inventories.
  
• Affiliated Computer (NYSE: ACS) was upgraded to Buy from Hold at Jefferies based on valuation and expectations for better bookings.

MOST NOTEWORTHY: K-12 Inc., ChinaEdu and Cardtronics were today's noteworthy initiations:

• Baird is positive on K-12 Inc. (NYSE: LRN)'s leadership position and growing market opportunity for expansion. The firm started shares with an Outperform rating and $26 target. Shares were also initiated at Morgan Stanley with an Equal Weight rating and at Credit Suisse with an Outperform rating.
• Bear initiated ChinaEdu (NASDAQ: CEDU) with an Outperform rating and $11.20 target and said demand for post-secondary education in is outstripping the capacity of land based universities and that CEDU will benefit from the governments strategy to raise education levels. Piper, which started shares with a Buy rating and $10 target, believes the online higher education market is still in the relatively early stages as online student enrollments represent less than one-fourth of total university enrollments.
• William Blair believes Cardtronics (NASDAQ: CATM) has a highly attractive opportunity to increase the number of ATM sites it operates. The firm assumed coverage with an Outperform rating.

Other initiataions:

• MedAssets (NASDAQ: MDAS) was initiated with an Overweight rating and $24 target at Lehman, at Deutsche Bank with a Buy rating and $25 target and at Wachovia with a Market Perform rating.
• Jefferies initiated VanceInfo (NYSE: VIT) with a Buy rating and $11 target.
• Susquehanna initiated Under Armour (NYSE: UA) with a Neutral rating.

In the U.S., there are about 5,700 acute care health systems. No doubt, they face lots of pressure from things like reimbursement, rising costs, government regulation, and so on. In fact, according to a study from the American Hospital Association, about 25% of community hospitals had negative margins.

Well, for MedAssets this is a big opportunity. And, to help propel the growth, the company has filed for an IPO.

Basically, the company has technology that helps improve operating margins and cash flows for hospitals. The improvements typically range from 1.5% to 5.0% of revenues. A critical piece of the technology is MedAssets' proprietary database, which includes 4 million products and information on 160,000 different charges.

It's turned out to be a great business. Over the past four years, MedAssets revenues have shown a compound annual revenue growth rate of 41.4%. As of last year, revenues were $146.2 million and adjusted EBITDA was $50.8 million. Keep in mind that MedAssets estimates that the size of its market is roughly $6.5 billion.

The lead underwriters on the IPO include Morgan Stanley (NYSE: MS) and Lehman Brothers (NYSE: LEH). The proposed ticker is MDAS. You can find the prospectus at the SEC website.

Also, if you want to check out more IPO filings, click here.

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Edgar Online Guide to Decoding Financial Statements.