Rod,
re: "certain events":
Rule 10b5-1 -- Trading "on the Basis of" Material Nonpublic Information in Insider Trading Cases
a. General. The "manipulative and deceptive devices" prohibited by Section 10(b) of the Act and Rule 10b-5 thereunder include, among other things, the purchase or sale of a security of any issuer, on the basis of material nonpublic information about that security or issuer, in breach of a duty of trust or confidence that is owed directly, indirectly, or derivatively, to the issuer of that security or the shareholders of that issuer, or to any other person who is the source of the material nonpublic information.
Basically, the certain events that you refer to are any events that are "material" and have not been made public.
