Damon (DMN) shares fell over 48% in recent Monday premarket activity, extending Friday's loss.
Vaxcyte (PCVX) stock slipped more than 29%, adding to the previous session's fall.
Canada Goose Holdings (GOOS) shares were down 6% after Barclays downgraded the stock to underweight from equalweight with a price target of 11.45 Canadian dollars ($8).
Rocket (RKT) stock fell more than 4% after saying it has agreed to acquire Mr. Cooper (COOP) in an all-stock transaction valued at $9.4 billion.