Microeconomic analysis separates the borrower’s ability to repay from the incentive to do so. A decline in income or asset values can reduce available resources, while the cost of repayment may become high relative to the borrower’s expected benefit from continuing payment. Default becomes more likely when either weakened ability or reduced incentive pushes repayment below its perceived cost.
Collateral and screening change the terms under which credit is supplied. Collateral gives lenders an additional protection when repayment fails, while screening helps them assess borrowers before extending funds. These tools can influence who receives credit, the conditions attached to borrowing, and the distribution of default risk between borrowers and lenders.
Income shocks, asset-price declines, and changes in borrowing conditions can each increase default risk through different channels. Lower income directly weakens repayment capacity, while falling asset prices can reduce the value supporting a loan. Changes in borrowing conditions may raise the cost of repayment or alter incentives, making existing obligations harder to sustain.
A model can compare the borrower’s ability or incentive to repay with the cost of meeting the loan terms. Researchers then examine how changes in income, asset prices, or borrowing conditions alter that comparison. The resulting analysis can connect individual repayment decisions to lender losses, credit availability, and financing choices by households or firms.
When perceived default risk increases, lenders may adjust interest rates, require collateral, strengthen screening, or impose credit limits. These responses change the price, security, or availability of borrowing rather than treating every applicant identically. In aggregate, such decisions can produce credit rationing, limiting financing for some borrowers even when they seek loans.
Default analysis helps explain how households and firms make financing decisions and how lenders absorb or redistribute losses. It also informs the design of bankruptcy rules and financial regulation, which shape the consequences of failed repayment and the incentives facing both sides of a loan contract. These applications connect individual credit outcomes with broader market arrangements.