Tuesday's Analysts' Upgrades and Downgrades

CHANGE IN RATINGS

Accuray (ARAY Quote) initiated with Buy rating at Jefferies. Price target begins at $29 and 2007 EPS estimates set at $0.82.

Express Scripts (ESRX Quote) upgraded to Buy rating from Neutral at UBS. Price target jumps to $99 from $77 and 2007 EPS estimates rise to $4.31 from $3.98.

Gilead (GILD Quote) was upgraded from Neutral to Buy at Merrill Lynch. $91 price target. Long-term growth prospects are improving for the HIV franchise, and new product launches could perform ahead of expectations.

Medimmune (MEDI Quote) was downgraded to Peer Perform at Bear Stearns. Upside could be limited over the next 6 to 12 quarters, unless the stock is taken over.

Credit Suisse is downgrading Oneok (OKE Quote) to Neutral from Outperform based on valuation. Stock has essentially reached target price of $46.

PPG Industries (PPG Quote) was upgraded from Hold to Buy at Deutsche Bank. $80 price target. Company is more likely to sell its chlor-alkali division, which has been depressing the valuation.

Praxair (PX Quote) was upgraded to Buy at Merrill Lynch. $70 price target. Stock has pulled back more than 30% from its highs, and revenue growth is set to rebound over the coming quarters.

Switch & Data (SDXC Quote) was initiated with a Buy rating at Jefferies. Price target begins at $22 and 2007 EPS estimates set at $0.09.