“Amortization Requirements May Increase Household Debt : A Simple Example,” IMF Working Paper No. 16/83, April 2016.
The idea is very simple. If you like to have a mortgage of SEK 2 million the next 10 years, you would take out an interest-only mortgage of SEK 2 million now and keep it for 10 years. However, if you learn that new amortization requirements imply that you have to pay back 2 percent of the initial mortgage every year, you would prefer to borrow SEK 2.5 million now, put the extra SEK 0.5 million in a savings account, and then use withdrawals from the savings account to amortize 2 percent of SEK 2.5 million each year, that is, SEK 50,000 each year and SEK 500,000 in 10 years. Thus, if an LTV cap is not binding you would borrow SEK 2.5 million, or as much as the LTV cap allows you to borrow.
Debt amortization requirements have been suggested as a way to reduce household indebtedness. However, a closer look reveals that amortization requirements may create incentives for both borrowers and lenders to borrow and lend more rather than less. Suppose that a household plans to finance a given housing purchase through a preferred future mortgage path. If that mortgage path violates a new amortization requirement, the household can still achieve its preferred mortgage path, net after savings, by initially borrowing more, investing the excess borrowing in a savings account, and fulfilling the amortization requirement by withdrawals from the savings account over time. This is obvious, if the savings interest rate equals the mortgage rate, because then the excess borrowing is costless. But even if the savings interest rate is less than the debt interest rate, so that the excess borrowing is costly, there remains a strong incentive to initially borrow more than without an amortization requirement. Furthermore, under these circumstances, it is profitable and quite riskless for banks to let borrowers borrow more and invest the excess borrowing in a savings account in the bank, giving lenders an incentive to lend more, not less, than without amortization requirements. Thus, amortization requirements as a way of reducing household indebtedness may be counterproductive.