SO this is a reverse pump-and-dump? Down-talk your company on an earnings call while giving people reason to question your intelligence, wait for the stock to drop, then buy. I am not a lawyer or securities regulator, but how is this not insider trading? Does he just have to wait X number hours after the earnings call before buying?
Insider trading requires material, non-public information. Rants aren't per se material representations, I don't think, and unless he misrepresented substantive disclosures and guidance (thus keeping the truth secret) he wouldn't have been trading on non-public information.
As a board member and major shareholder he's likely to see (and probably already has, many times) shareholder lawsuits claiming he violated a fiduciary duty in failing to consider shareholder interests and protecting the market value of shares. But it might be hard to show damages if the stock picks up as Musk seems to be betting.
If we're cynical, the act of buying more stock may be an attempt to color his behavior and put it in a favorable light in expectation of such shareholder lawsuits if the stock does drop longterm. That is, make it easier to argue that people were unreasonably construing his rants. I don't think his intentions matter in terms of liability--they're supposed to be judged by an objective standard--but in as much as Musk has a history of this behavior yet is still a very successful businessman with successful ventures, Musk himself partly defines what's objectively reasonable behavior and what are objectively reasonable reactions to that behavior. Reasonable isn't always defined by how the majority of people behave; it can be defined by what it takes to find success for yourself and others.
