In a recent article over at Fortune, I explore what Transferwise, a fast-growing new startup has rediscovered: an enduring customer need that is currently featuring in the migrant crisis, Hawala. The practice of Hawala originated centuries ago when traders were concerned that they would be waylaid by bandits along their routes of travel. So they worked out a trust-based practice in which a party in one location would receive a payment, and a trusted counterparty in a second location would pay the money owed. The key thing here is that the money itself doesn't change location - between payments in and out, the exchanges mostly balance themselves out.