Well, banking is a service and the MFI loans carry an average interest of about 25-35% (I assume). Each outside org (Kiva, C-4, Acumen, others) is an outside entity and the team members work with those groups to manage the local business on the ground. Each "partner" org does things somewhat differently, so in essence each one becomes a different "service offering" within the coop.

So let's say a business unit of 5 people has $500 USD in pledges/donations towards their launch, but they need $1,750 USD total. The banking unit looks at the 5 members and helps determine which "financial instrument" (ie. Kiva, C-4, etc) best suits the needs of that business...and those 5 people. Each take a loan of $250 USD, take a loan as a group of $1,250 USD, take the time to build out more donations, pre-sell some product/service to make sure the cash flow will be there.

Something along those lines perhaps.