SAC (Constant Amortization System)

Under the SAC (Constant Amortization System), the principal amortization is fixed across every installment. Since interest is charged on the outstanding balance (which shrinks month by month), payments decrease over time: higher at the start and lower toward the end. Over the full term, the borrower pays less total interest than under the Price Table system.

The downside is the first installment — higher than the equivalent Price Table payment — which can reduce initial borrowing capacity. Public banks (Caixa, Banco do Brasil) typically offer both systems; the choice affects the approved loan amount.