Analyst upgrades 9-6-07: Refiners, MTZ, COGN, FRX and RTRSY

MOST NOTEWORTHY: Refiners, MasTec, Cognos, Forest Labs and Reuters Group were today's noteworthy upgrades:

Bernstein upgraded shares of Marathon Oil Corporation (NYSE: MRO), Tesoro Corporation (NYSE: TSO), Sunoco Incorporated (NYSE: SUN) and Valero Energy Corporation (NYSE: VLO) to Market Perform from Underperform.
MasTec Incorporated (NYSE: MTZ) was upgraded to Buy from Accumulate at Think Equity and to Buy from Hold at SMH Capital on valuation following yesterday's sell-off.
JP Morgan upgraded shares of Cognos Incorporated (NASDAQ: COGN) to Overweight from Neutral citing solid end demand, expanded sales capacity, indications that C8 adoption should see an uptick, and the Applix Inc (NASDAQ: APLX) acquisition.
Forest Laboratories Inc (NYSE: FRX) was upgraded to Buy from Hold at Jefferies, as the firm believes Forest's victory in the Lexapro patent case eliminates a major overhang and returns the focus to the company's pipeline.
Lehman upgraded shares of Reuters Group (NASDAQ: RTRSY) to Overweight from Equal Weight to reflect benefits from the company's merger with Thomson Corporation (NYSE: TOC).

OTHER UPGRADES:

UBS upgraded shares of General Mills Inc (NYSE: GIS) to Buy from Neutral.
Thornburg Mortgage (NYSE: TMA) was upgraded to Sector Perform from Underperform at RBC Capital Markets.
CIBC World Markets upgraded EDO Corporation (NYSE: EDO) to Sector Outperformer from Sector Performer.
Bernstein upgraded shares of Rio Tinto (NYSE: RTP) to Outperform from Market Perform and shares of Anglo American (NASDAQ: AAUK) to Market Perform from Underperform.