A columnist at Bloomberg suggested yesterday that the most likely options were Toronto, Boston, Washington, Atlanta, Dallas or Denver. Whether not being in USA helped or hindered Toronto was a question asked, but not answered, although a sub-header wonders if five of the six cities could be "eliminated by politics".
https://www.bloomberg.com/view/artic...w-headquarters
Part of me wonders whether this whole exercise isn't some sort of political "shot across the bow" of the Trump administration.