I was thinking about unlucky numbers, and how thirteen was probably not the slightest bit unlucky in the wizarding world.  Then I recalled the lack of thirteenth floors (so to speak) in high rise buildings.  Well, why weren’t they there, really?  The obvious answer:  that floor was reserved for Wizard businesses!  I decided that this was by law — the elevator companies, no doubt, are all run by magical creatures of some sort.  Of course, the problem is that very wealthy, perhaps even international corporations must be renting out these expensive floors.  Otherwise, they would just set up in Diagon Alley.

Considering the Lovegoods, I came up with three pretty solid ideas for occupants.  I won’t mention the other two, as they may yet appear in the story.  My thanks to Y!A users who helped me to become more familiar with the types of businesses likely to be found in skyskrapers.