Yahoo CEO Marissa Mayer will leave Altaba and join Verizon. The structure of the deal, comprised of Yahoo's "core," and Altaba, previously called the informal "RemainCo," stemmed from a strategy to avoid capital gains tax during a divestiture. Before the Verizon deal, Yahoo had also considered plans to spin off a new public holding company, Aabaco, as a vehicle to distribute shares of Alibaba to shareholders. To be sure, Verizon's deal to buy Yahoo hasn't closed yet, amid the disclosure of two massive hackings.