Have you heard of the Grameen Bank? Economist Muhammad Yunus @grameen.bank had a theory: He believed that small, collateral-free loans could enable Bangladesh’s unbanked poor to start businesses and lift themselves out of poverty. Grameen Bank, chartered in 1983, proved him right, demonstrating that “microcredit” could be self-sustaining and even profitable. Since then, Grameen has loaned $17.4 billion to 8.7 million borrowers, most of them impoverished women; it reports a 98.3% repayment rate and has had only three money-losing years since 1990. Just as important is the movement for which Grameen paved the way. Globally, microfinance accounts for at least $60 billion in loans annually and has reached 135 million people, according to the World Bank—one reason Yunus’s accolades include the 2006 Nobel Peace Prize via @grameen_foundation.