Doesn't need to be a conspiracy, where somebody is getting rich at the company's expense.
At work we have something similar, where every few years the IT department tenders the 'preferred supplier' for general IT stuff. The logic is basically that by promising the vendors exclusivity, they will bid lower. So yes, sometimes that means we'll pay 3x for a keyboard compared to the price we'd pay at the local discount computer store; I think in general the prices for the stuff that is in the 'tendering portfolio' is very competitive, otherwise it's list price.
OTOH, we save money since the billing from the preferred supplier is worn-in standard procedure, and also employees don't waste company time searching the web for the cheapest/best/whatever keyboard.
