Pandora Media ( P ) has received a flurry of stock rating downgrades and price-target cuts since announcing an investment from Sirius XM Holdings ( SIRI ) last Friday. Pandora stock had been elevated in recent months by hopes that the money-losing streaming music service would be purchased by Liberty Media ( LSXMA ), majority owner of Sirius XM. But instead, subscription radio service Sirius XM is making a $480 million strategic cash investment in Pandora. It agreed to buy convertible preferred stock in Pandora that represents 19% of the company's currently outstanding common shares and a 16% stake on an as-converted basis. On Monday, Oppenheimer and Citigroup downgraded Pandora to market perform, or neutral. FBR cut its price target on the stock to 11 from 14, but revised its rating to outperform from market perform. On Wednesday, Needham lowered its price target on Pandora to 11 from 16, but maintained its buy rating.