Four billion low-income consumers make up the majority of the world's population and constitute the base of the economic pyramid. These consumers represent significant opportunities for market-based approaches to better meet their needs and increase their productivity and incomes. Spending on housing by those at the base of the pyramid reflects strong consistent demand, with people willing to spend a fair share of their income on their home. However, informal home ownership poses a barrier to service delivery, as many governments require proof of title to receive benefits and municipalities are reluctant to connect undocumented homes to utilities when they have no legal means to collect unpaid fees.