+1 for the squeaky wheel. If these companies are large enough to have accounts payable departments, it's often standard to keep onto company money for as long

+1 for the squeaky wheel. If these companies are large enough to have accounts payable departments, it's often standard to keep onto company money for as long as possible. If they can eke out a few more days of interest they will. If you're persistent (read annoying) enough, they'll want to pay just to stop you calling every day.