Analyst upgrades:

• Piper Jaffray upgraded PetMed Express (NASDAQ: PETS) to Overweight from Neutral following the better-than-expected Q1 results. The firm raised its target on shares to $22 from $19.
• Deutsche Bank upgraded International Paper (NYSE: IP) and Packaging Corp. (NYSE: PKG) to Buy from Hold to reflect stabilization in the containerboard industry. The firm raised its target price on Packaging Corp. to $24 from $14, and on International Paper to $24 from $16.
• Bernstein upgraded Human Genome Sciences (NASDAQ: HGSI) to Outperform from Market Perform following the positive Phase III data for Benlysta in lupus.
• IBM (NYSE: IBM) was upgraded to Hold from Sell at Societe Generale.
• British Airways (OTC: BAIRY) was upgraded to Buy from Sell at Goldman.
• Continental AG (OTC: CTTAY) was upgraded to Hold from Sell at Citigroup.

MOST NOTEWORTHY: Athenahealth, Marvell Technology, Broadcom and Nvidia were today's noteworthy initiations:

• Athenahealth (NASDAQ: ATHN) was initiated with a Neutral rating at Goldman Sachs. Jefferies started shares of the stock with a Buy rating and $46 target, as they believe their estimates could prove conservative given potential upside from new and existing physicians adopting athenaClinicals.
• Kaufman Bros initiated Marvell Technology (NASDAQ: MRVL) with a Hold rating and $18 target, as they believe near-term growth prospects remain uncertain and recommends waiting for more favorable entry points.
  
• The firm also initiated Broadcom Corporation (NASDAQ: BRCM) with a Hold rating and $35 target, and believes the company's growth prospects are priced into shares following the recent rally, and started shares of Nvidia Corporation (NASDAQ: NVDA) with a Buy rating and $42 target, as they believe the company's growth opportunity and competitive strength remain intact and would be buyers at current levels.

OTHER INITIATIONS:

• Goldman started shares of Sara Lee (NYSE: SLE) with a Neutral rating and $16 target.
  
• UBS initiated US BioEnergy (NASDAQ: USBE) with a Neutral rating.
  
• Bear Stearns inititated CarMax (NYSE: KMX) with an Underperform rating.
  
• Wachovia started Teekay Offshore Partners (NYSE: TOO) and Holly Energy Partners (NYSE: HEP) with Market Perform ratings.

MOST NOTEWORTHY: Granite Construction Inc (GVA), Sunterra Corp (SNRR), Halliburton Co (HAL) and Golfsmith International Holdings, Inc (GOLF) were today's notable downgrades:

• Matrix USA downgraded Granite Construction Inc (NYSE: GVA) to Sell from Buy on valuation.

• CL King cut Sunterra Corp (OTC: SNRR) to Neutral from Strong Buy.

• UBS removed Halliburton Co (NYSE: HAL) from its U.S. Strategic Stock Selections List.

• JP Morgan cut Golfsmith (NASDAQ: GOLF) to Neutral from Overweight, cutting risk to full-year guidance.

OTHER DOWNGRADES:

• Bank of America cut Spirit Finance Corp (NYSE: SFC) to Neutral from Buy following news that an Australia-based consortium led by Macquarie Bank Ltd will acquire Spirit for $14.50/share.

• Baird downgraded Diamond Management & Technology Consultants Inc (NASDAQ: DTPI) to Neutral from Outperform following its lowered Q4 outlook.

• Goldman cut Holly Energy Partners (NYSE: HEP) to Neutral from Buy on valuation.

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