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.

Analyst upgrades:

• Wachovia upgraded shares of Exelon (NYSE: EXC) to Outperform from Market Perform to reflect the company's attractive nuclear fleets and strong operational track record.
  
• Jesup & Lamont upgraded Ormat Technologies Inc. (NYSE: ORA) to Buy from Hold on valuation and increasing visibility on near-term Products revenue.
  
• RBC Capital upgraded Memc Electronic (NYSE: WFR) to Outperform from Sector Perform on expectations of improved demand growth following the likely eight-year extension of the US solar tax credit program.
• AmBev (NYSE: ABV) was raised to Outperform from Neutral at Credit Suisse.
  
• AmerisourceBergen (NYSE: ABC) was upgraded at Merrill Lynch to Buy from Neutral.
  
• Piper upgraded Anadys Pharma (NASDAQ: ANDS) to Neutral from Sell.

Analyst downgrades: