Kriegspieler said:No, they don't. POPs buy directly from the WM, which is why the best thing you can do is to give up your stockpiles of things, although the effect is one-off.
While they buy off the WM your pops get first shot at the goods you produce. So when you sell goods to the WM first your pops get to buy what they need from them then it goes into the WM pool and that is sold to countries in order of prestiege.