Because the poor have no collateral to offer, Yunus keeps borrowers on the straight and narrow with a system of "solidarity lending." The system creates solidarity groups of five people. Should any one of them default on a loan, the remaining four become ineligible to borrow for several years. In tightly knit rural communities where honor is prized, this is a very effective means of applying peer pressure and oversight.
由於窮人無力提供擔保品，於是尤努斯以 5 人互保（其中一人無法還款，其餘 4 人在未來幾年內都將無法獲得貸款）的方式來規範，這在人際關係緊密且極重榮譽的農村裡，顯然發揮了互相督促、監督的功效。