Don't overlook the forest for a tree. You have to look at what specific regulations Grifco had violated. The foundation of SEC regulations is the Securities Act of 1933, Exchange Act of 1934, and more recently the Sarbanes Oxley Act.
It doesn't matter if they bought the share on the info or not. By law Grifco, as a public company, is responsible to disclose all material information as stated in the Securities Exchange act of 1934 Rule 10b-5
Rule 10b-5 -- Employment of Manipulative and Deceptive Devices
It shall be unlawful for any person, directly or indirectly, by the use of any means or instrumentality of interstate commerce, or of the mails or of any facility of any national securities exchange,
To employ any device, scheme, or artifice to defraud,
To make any untrue statement of a material fact or to omit to state a material fact necessary in order to make the statements made, in the light of the circumstances under which they were made, not misleading, or
To engage in any act, practice, or course of business which operates or would operate as a fraud or deceit upon any person,
in connection with the purchase or sale of any security.
It doesn't seem that difficult to prove how JD violated the above regulation. In fact, IMO he's violated the above dozens of times. So why haven't SEC acted yet?