What is Bottom of the pyramid?

In economics, the bottom of the pyramid is the largest, but poorest socio-economic group. In global terms, this is the four billion people who live on less than $2 per day, typically in developing countries. The phrase “bottom of the pyramid” is used in particular by people developing new models of doing business that deliberately target that demographic, often using new technology. This field is also often referred to as the "Base of the Pyramid" or just the "BoP".

The more current usage refers to the 4 billion people living on less than $2 per day, as first defined in 1998 by Professors C.K. Prahalad and Stuart L. Hart. It was subsequently expanded upon by both Prahalad in 2004 in The Fortune at the Bottom of the Pyramid and by Hart in 2005 in Capitalism at the Crossroads.
Prahalad proposes that businesses, governments, and donor agencies stop thinking of the poor as victims and instead start seeing them as resilient and creative entrepreneurs as well as value-demanding consumers. He proposes that there are tremendous benefits to multi-national companies who choose to serve these markets in ways responsive to their needs. After all the poor of today are the middle-class of tomorrow. There are also poverty reducing benefits if multi-nationals work with civil society organizations and local governments to create new local business models.

Micro-credit
As The Economist reported on August 11th, 2005, one example of “bottom of the pyramid” is the growing microcredit market in South Asia, particularly in India. With technology being steadily cheaper and more ubiquitous, it is becoming economically efficient to “lend tiny amounts of money to people with even tinier assets”. The firm discussed in the article, Sa-Dhan, argues that the availability of credit to the poor “helps the poor but allows banks to increase their business”.