Catch up on today's top five analyst downgrades with this list compiled by The Fly: 1. Roku (ROKU) downgraded to Underweight from Equal Weight at Morgan Stanley with analyst Benjamin Swinburne saying Roku continues to execute a "sound strategy" to capitalize on the shift to streaming, but there are risks to growth expectations not reflected in current valuation levels. 2. Western Digital (WDC) resumed with a Hold from Buy at Stifel with analyst Patrick Ho saying he sees some tailwinds for the company but has "some more fundamental questions" as it relates to Western Digital versus Seagate Technology (STX). 3. Philip Morris (PM) downgraded to Neutral from Buy at Citi. 4. Biogen (BIIB) downgraded to Underperform from Neutral at Baird with analyst Brian Skorney saying the upcoming Clinical Trials on Alzheimer's Disease annual congress could serve as a negative catalyst for shares Biogen shares. 5. Deere (DE) downgraded to Underperform from Neutral at BofA/Merrill with analyst Ross Gilardi saying he views last week's earnings outlook as disappointing and says it is "more realistic than conservative." This list is just a portion of The Fly's full analyst coverage. To see The Fly's full Street Research coverage, click here.