In a gleaming office tower in Mexico City secured with retinal scanners, bulletproof glass, and armed guards, dozens of workers in white lab coats dart around a large operations center monitoring long rows of computers. Along one wall, 54 enormous screens flicker dizzyingly with numbers, graphs, and fever charts: a relentless stream of data. You'd think the urgent mission involved tracking the trajectory of a spacecraft or the workings of a national power grid, not tiny amounts of cash and credit for Mexico's working poor.
The transactions are so minuscule they hardly seem worth the bother. The average loan amounts to $257. But for Banco Azteca, a swiftly growing bank affiliated with Latin America's largest household retailer, the small sums represent a torrent of revenue that has caught even its founders by surprise. For three decades, micro-lending was seen as a tool of nonprofit economic development. Now poor people are turning into one of the world's least likely sources of untapped profit, primarily because they will pay interest rates most Americans would consider outrageous, if not usurious.