Catch up on today's top five analyst downgrades with this list compiled by The Fly: 1. ON Semiconductor (ON) downgraded to Neutral from Buy at Goldman Sachs with analyst Mark Delaney citing the stock's relative outperformance and lack of catalysts over the next year. 2. Nordstrom (JWN) downgraded to Hold from Accumulate at Gordon Haskett. 3. Mallinckrodt (MNK) downgraded to Neutral from Buy at Mizuho with analyst Irina Koffler saying Mallinckrodt consists of a gradually declining generics portfolio, and a "basket" of branded assets that face some degree of competition and downside risks. 4. Whiting Petroleum (WLL) downgraded to Underweight from Equal Weight at Morgan Stanley with analyst Drew Venker citing weak risk-reward relative to peers. 5. GasLog (GLOG) downgraded to Hold from Buy at DNB Markets. This list is just a portion of The Fly's full analyst coverage. To see The Fly's full Street Research coverage, click here.

Exane BNP Paribas analyst David O'Connor downgraded ON Semiconductor to Underperform from Neutral with a $55 price target.