Poor individuals and firms struggle to borrow because they lack collateral and credit history, making it hard for lenders to assess repayment capacity. This prevents profitable investments in education, equipment, and business startup, locking households in low-income equilibria. Relaxing constraints through mobile money, group lending, or collateral substitutes can unlock growth.
From your study of poverty traps, you know that households can be stuck in low-income equilibria where small improvements are not enough to escape poverty. Credit constraints are one of the most powerful mechanisms that create and sustain these traps. The logic is straightforward: a farmer who could double her income by buying a better plow, or a young person who could earn far more with vocational training, cannot make these investments because they cannot borrow the money — and they cannot borrow the money because they are poor.
The root of the problem is information asymmetry, which you have studied in microeconomics. Lenders face two classic problems. Adverse selection means they cannot easily distinguish borrowers who will repay from those who will not, so they either charge high interest rates (driving away safe borrowers) or ration credit entirely. Moral hazard means that once someone has borrowed, the lender cannot easily monitor how the funds are used — a borrower might take on excessive risk, knowing the lender bears the downside. In wealthy countries, these problems are mitigated by collateral (the bank can seize your house), credit scores (your history is tracked), and legal enforcement (courts compel repayment). In developing countries, the poor have no collateral to pledge, no formal credit history, and the legal system may be too slow or costly to enforce contracts.
The result is a credit market that systematically excludes the poor. Formal banks serve salaried workers and established businesses; the poor turn to informal moneylenders who charge extremely high interest rates — sometimes 100% or more annually — because their own costs of screening and enforcement are high. At these rates, only the most desperate or the most reckless borrow, which reinforces the lender's belief that poor borrowers are risky. This is a self-reinforcing cycle: poverty causes exclusion from credit markets, and exclusion from credit markets perpetuates poverty.
Innovations in development finance have attacked this problem from multiple angles. Microfinance and group lending (pioneered by Grameen Bank) replace collateral with social pressure: borrowers form groups and are jointly liable for each other's loans, creating peer monitoring that reduces moral hazard. Mobile money platforms like M-Pesa reduce transaction costs and create digital payment histories that serve as informal credit scores. Conditional cash transfers and savings commitment devices help households accumulate the small amounts of capital needed to cross investment thresholds. The evidence on these interventions is mixed — microfinance, for example, has modest effects on average income but significant effects on consumption smoothing and business investment for a subset of borrowers. No single intervention eliminates credit constraints, but together they chip away at the barriers that keep profitable investments from reaching the people who need them most.