That was some seriously Bad news for Symantec as a share drop on 33% is pretty much and in this case they lost $6 billion according to the article. Seams Symantec is cursed with bad luck or is it just incompetent leadership.
Google will distrust all existing Symantec SSL certificates starting with October 2018, and Symantec will have to rebuild its entire certificate issuance infrastructure from scratch if it wants to remain in the CA (Certificate Authority) business.