Adverse Selection
Adverse selection occurs when lenders do not know particular characteristics of borrowers; for example, a lender may be uncertain about a borrower's
preferences for undertaking risky projects. (For analyses of credit markets under such conditions, see Jaffee and Russell 1976 and Stiglitz and Weiss 1981.)
One much-discussed implication is that lenders may consequently reduce the
amount that they decide to lend, resulting in too little investment in the economy. Ultimately, credit could be rationed.
The typical framework for analyzing such problems is as follows. Suppose
that the projects to which lenders' funds are allocated are risky and that borrowers sometimes do not earn enough to repay their loans. Suppose also that
funds are lent at the opportunity cost of funds to the lenders (say, the supply
price paid to depositors). Lenders will thus lose money because sometimes individuals do not repay. Therefore, lenders must charge a risk premium, above
their opportunity costs, if they wish to break even. However, raising the interest rate to combat losses is not without potentially adverse consequences for
the lender.
Suppose (as do Stiglitz and Weiss 1981) that all projects have the same mean
return, differing only in their variance. To make the exposition easier, suppose
also that all borrowers are risk neutral. The adverse selection problem is then
characterized as individuals having privately observed differences in the riskiness of their projects. If the interest rate is increased to offset losses from defaults, it is precisely those individuals with the least risky projects who will
cease to borrow first. This is because these individuals are most likely to repay
their loans and hence are most discouraged from borrowing by facing higher
interest rates. By contrast, those who are least likely to repay are least discouraged from borrowing by higher interest rates. Profits may therefore decrease
as interest rates increase beyond some point. A lender may thus be better off
rationing access to credit at a lower interest rate rather than raising the interest
rate further.
The key observation here is that the interest rate has two effects. It serves
the usual allocative role of equating supply and demand for loanable funds,
but it also affects the average quality of the lender's loan portfolio. For this
reason lenders may not use interest rates to clear the market and may instead
fix the interest rate, meanwhile rationing access to funds.
A credit market with adverse selection is not typically efficient, even according to the constrained efficiency criterion discussed above. To see this, consider
what the equilibrium interest rate would be in a competitive market with adverse selection. Because all borrowers are charged the same interest rate, the
Adverse SelectionAdverse selection occurs when lenders do not know particular characteristics of borrowers; for example, a lender may be uncertain about a borrower'spreferences for undertaking risky projects. (For analyses of credit markets under such conditions, see Jaffee and Russell 1976 and Stiglitz and Weiss 1981.)One much-discussed implication is that lenders may consequently reduce theamount that they decide to lend, resulting in too little investment in the economy. Ultimately, credit could be rationed.The typical framework for analyzing such problems is as follows. Supposethat the projects to which lenders' funds are allocated are risky and that borrowers sometimes do not earn enough to repay their loans. Suppose also thatfunds are lent at the opportunity cost of funds to the lenders (say, the supplyprice paid to depositors). Lenders will thus lose money because sometimes individuals do not repay. Therefore, lenders must charge a risk premium, abovetheir opportunity costs, if they wish to break even. However, raising the interest rate to combat losses is not without potentially adverse consequences forthe lender.Suppose (as do Stiglitz and Weiss 1981) that all projects have the same meanreturn, differing only in their variance. To make the exposition easier, supposealso that all borrowers are risk neutral. The adverse selection problem is thencharacterized as individuals having privately observed differences in the riskiness of their projects. If the interest rate is increased to offset losses from defaults, it is precisely those individuals with the least risky projects who willcease to borrow first. This is because these individuals are most likely to repaytheir loans and hence are most discouraged from borrowing by facing higherinterest rates. By contrast, those who are least likely to repay are least discouraged from borrowing by higher interest rates. Profits may therefore decreaseas interest rates increase beyond some point. A lender may thus be better offrationing access to credit at a lower interest rate rather than raising the interestrate further.The key observation here is that the interest rate has two effects. It servesthe usual allocative role of equating supply and demand for loanable funds,but it also affects the average quality of the lender's loan portfolio. For thisreason lenders may not use interest rates to clear the market and may insteadfix the interest rate, meanwhile rationing access to funds.A credit market with adverse selection is not typically efficient, even according to the constrained efficiency criterion discussed above. To see this, considerwhat the equilibrium interest rate would be in a competitive market with adverse selection. Because all borrowers are charged the same interest rate, the
การแปล กรุณารอสักครู่..
