Analysts' Upgrades, Downgrades: Merck

Change in Ratings

AES (AES Quote) upgraded at Merrill from Underperform to Neutral. $10 price target. Valuation call, as the stock is down 69% year-to-date, and the stock is not crediting recent growth.

Acme Packet (APKT Quote) downgraded at Credit Suisse to Neutral from Outperform. Cites challenging carrier cap-ex environment and deteriorating global macro-environment. Lowered target price to $4 from $6.

Career Education (CECO Quote) upgraded at Piper Jaffray to Neutral from Sell based on valuation and lack of major negative catalysts. See potential for continued difficulty driven by troubled state of culinary and art and design segments, but believe shares adequately reflect this. Price target raised to $14 from $13. ...