Catch up on today's top five analyst upgrades with this list compiled by The Fly: 1. Micron (MU) was upgraded to Buy from Hold at Cross Research, to Buy from Underperform at Needham, and to Buy from Hold at Summit Redstone. 2. Sunoco (SUN) upgraded to Outperform from Market Perform at FBR Capital with analyst Robert Balsamo saying the credit facility amendments announced reduce the need for a distribution cut. The analyst has a $32 price target for the shares. 3. National Instruments (NATI) upgraded to Outperform from Neutral at Baird with analyst Richard Eastman saying he sees the potential for accelerating revenue growth over the next few years combined with more determined focus to deliver operating leverage. 4. Merus (MRUS) upgraded to Buy from Neutral at Citi with analyst Yigal Nochomovitz saying the Incyte (INCY) collaboration deal has "very favorable" terms. 5. Sucampo (SCMP) upgraded to Buy from Neutral at Mizuho with the firm citing the sell-off in shares post the $260M convertible raise. This list is just a portion of The Fly's full analyst coverage. To see The Fly's full Street Research coverage, click here.