The bottom of the pyramid which actually means the bottom of the wealth pyramid or the bottom of the income pyramid is the largest, but poorest socio-economic group. In global terms, this is the four billion people who live on less than say $3,000 per year. 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. Several articles have been written on the potential market by members of business schools offering consultancy on the burgeoning market. They include The Fortune at the Bottom of the Pyramid by C.K. Prahalad of the University of Michigan, Capitalism at the Crossroads by Stuart L. Hart of Cornell University and the first empirical article, Reinventing strategies for emerging markets: Beyond the transnational model, by Ted London of the University of Michigan and Hart.
The phrase “bottom of the pyramid” was used by U.S. president Franklin D. Roosevelt in his April 7, 1932 radio address, The Forgotten Man, in which he said "These unhappy times call for the building of plans that rest upon the forgotten, the unorganized but the indispensable units of economic power...that build from the bottom up and not from the top down, that put their faith once more in the forgotten man at the bottom of the economic pyramid."
The more current usage refers to the billions of 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 in their books: The Fortune at the Bottom of the Pyramid by Prahalad in 2004 and Capitalism at the Crossroads by Hart in 2005.
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.