The internal process inside a company to approve the issue of a purchase order to a supplier. The more money required, the more signatures required... plus the more likely the spend will need to be validated by a detailed investment and business case.
Just because one person inside a company wants to spend money building their little empire doesn't mean that approval of the spend is guaranteed! There are other people to persuade - the CEO (MD), the CFO (FD) and the more you want to spend, the better the business arguments have to be. The SHARK tools do exactly this.