The idea that workers in wealthy countries like the United States are part of a “labor aristocracy” bought off with the fruits of imperialism is nonsense. The best way to build a movement against US imperialism is to build the labor movement domestically.
Unfortunately I can't find numbers for US overseas investment by country, but it totals to thirty-one trillion (table A). Of that, six and a half trillion is Foreign Direct Investment which means investments that yield at least a 10% stake. Nearly four trillion (around 64%) of US FDI is in Europe which I think is a good indicator of where portfolio investments are as well. You can compare FDI data of countries here.
That's not the whole picture of course. For example US/global oil policy aims to control prices (via the OPEC cartel) so we garrison armies in Saudi Arabia even if we don't have huge investments there. There's also the military industrial complex which is extremely profitable and needs lots of troops to be stationed overseas to remain as such. Geostrategic positioning also plays a role, we put troops on the border of Russia's sphere of influence.