One of the case law requirements is that the seller has to show that it went through a competitive process to get its deal price. In its proxy statement, Sonic Corp. detailed how the possible-merger process started Dec. 14, 2017. That's when Southeastern Asset Management Inc. said at a meeting in Memphis, Tennessee, that it was going to file an amendment with the Securities Exchange Commission so that it could have more direct conversations with Sonic and other shareholders about the company's valuation and strategic matters.