Catch up on today's top five analyst upgrades with this list compiled by The Fly: 1. Regeneron (REGN) upgraded to Buy from Hold at SunTrust with analyst Robyn Karnauskas citing her "deep dive" analysis in the company's pipeline and conversations with its management in modeling additional revenue build with credit to its Libtayo, Dupi, fasinumab and oncology pipeline products. 2. Cisco (CSCO) upgraded to Overweight from Equal Weight at Morgan Stanley with analyst Meta Marshall saying while cognizant that Cisco's revenue will be challenged in the near to medium term from macro headwinds, the stock's multiple discount to the S&P is at 10-year highs despite the company's durable earnings growth. 3. Becton Dickinson (BDX) upgraded to Overweight from Equal Weight at Barclays with analyst Kristen Stewart saying the shares have lagged peers year-to-date, which reflects Alaris pump challenges, revision in guidance, and the market's "evolved thinking" around the company's growth outlook. 4. Six Flags (SIX) upgraded to Buy from Neutral at Janney Montgomery Scott with analyst Tyler Batory saying he sees the current valuation as attractive and prefers the company's park diversity and exposure to some of the largest market by population in the U.S. 5. Constellation Brands (STZ) upgraded to Buy from Hold at Argus with analyst John Staszak saying the company should emerge from the pandemic in a "position of strength." This list is just a portion of The Fly's full analyst coverage. To see The Fly's full Street Research coverage, click here.