Occupancy Fraud
  
The boon of money launderers everywhere. What better way is there, in fact, to launder drug money back into The System, than owning a dumpy apartment complex with no (or just very few) renters? And then miraculously being "Sold Out!" via occupancy fraud? If you've seen Breaking Bad, you know the same drill a la the car wash.
So you own a building with notionally 100 occupy-able apartments. Only 10 of them are rented at 2 grand a month. So you have 90 empty, where you can fraudulently claim that all 90 are occupied by, uh...Somebody Somethingstein...and multiply that 90 by 2 grand, and voila! You have laundered 180 grand a month of your ill-gotten fentenol distribution gains. Do this for a few years, and an easy 10 million bucks is laundered and "clean," courtesy of your occupancy fraud apartment building, the no-tell motel of its genre.