Catch up on today's top five analyst upgrades with this list compiled by The Fly: 1. Cognizant (CTSH) upgraded to Buy from Hold at HSBC. 2. Casey's General Stores (CASY) upgraded to Buy from Neutral at Northcoast with analyst Chuck Cerankosky saying management's plan to enhance earnings growth and shareholder value is well underway as demonstrated by Q1 results. 3. Occidental Petroleum (OXY) upgraded to Buy from Hold at Edward Jones. 4. Vale (VALE) upgraded to Neutral from Underperform at Exane BNP Paribas. 5. Targa Resources (TRGP) upgraded to Outperform from Market Perform at Wells Fargo with analyst Michael Blum saying with the addition of the Grand Prix pipeline, Targa should have a fully integrated suite of natural gas liquids logistics assets from gathering and processing in the Permian to pipeline to fractionation to liquefied petroleum gas export. This list is just a portion of The Fly's full analyst coverage. To see The Fly's full Street Research coverage, click here.