Inter-Dealer Broker

It's like a middleman between two larger financial institutions. The inter-dealer broker fills in the space when two organizations (like investment banks) want to trade something that doesn't have a structured market.

Global Bankers Mart, LLC wants to buy a cache of rare dinosaur egg fossils from Capital Investment Corp. GBM sees big upside in the fossilized egg market, and their Dino Long Fund has been looking for investments. However, the transaction is tricky, because unlike a stock, there's no current exchange where dino eggs get traded (apparently, the CME hasn't gotten in on that action yet).

So you step in as the inter-dealer broker. You become the intermediary in the deal, creating the bridge for the companies to close the transaction. The eggs get sent to GBM, and Capital Investment Corp. gets a wad of cash. You take a small commission for facilitating the deal.