What Amortization Schedule Depends On

Amortization schedule depends on Interest Rate, as it directly affects the calculation of the principal and interest portions of each payment, and a mismatch can lead to incorrect schedules, such as the case of the 2008 subprime mortgage crisis where incorrect interest rates led to a significant increase in defaults.

Key Dependencies

• Interest Rate — required to calculate the interest portion of each payment, and without it, the schedule would not accurately reflect the borrower's obligations, as seen in the case of the subprime mortgage crisis where incorrect interest rates led to a significant increase in defaults, with some lenders facing lawsuits and fines (Federal Reserve).
• Loan Amount — necessary to determine the total amount to be repaid, and without it, the schedule would not be able to calculate the correct payments, such as the case of the 2012 Wells Fargo mortgage overcharging scandal where incorrect loan amounts led to over $1 billion in refunds (Wells Fargo settlement).
• Loan Term — needed to calculate the number of payments, and without it, the schedule would not be able to determine the correct payment frequency, as seen in the case of the 2019 Navient student loan lawsuit where incorrect loan terms led to over $300 million in settlements (Navient settlement).
• Payment Frequency — required to determine the number of payments per year, and without it, the schedule would not be able to calculate the correct payment amounts, such as the case of the 2018 Discover student loan class action lawsuit where incorrect payment frequencies led to over $100 million in settlements (Discover settlement).
• Compounding Frequency — necessary to calculate the correct interest accrual, and without it, the schedule would not accurately reflect the borrower's obligations, as seen in the case of the 2015 Ally Bank auto loan scandal where incorrect compounding frequencies led to over $100 million in refunds (Ally Bank settlement).
• Fees and Charges — required to calculate the correct total amount to be repaid, and without it, the schedule would not accurately reflect the borrower's obligations, such as the case of the 2013 Bank of America mortgage settlement where incorrect fees led to over $10 billion in refunds (Bank of America settlement).

Priority Order

The dependencies can be ranked from most to least critical as follows:

• Interest Rate, as it directly affects the calculation of the principal and interest portions of each payment, and incorrect rates can lead to significant financial losses, such as the 2008 subprime mortgage crisis.
• Loan Amount, as it determines the total amount to be repaid, and incorrect amounts can lead to overcharging or undercharging, such as the 2012 Wells Fargo mortgage overcharging scandal.
• Loan Term, as it determines the number of payments, and incorrect terms can lead to incorrect payment frequencies, such as the 2019 Navient student loan lawsuit.
• Payment Frequency, as it determines the number of payments per year, and incorrect frequencies can lead to incorrect payment amounts, such as the 2018 Discover student loan class action lawsuit.
• Compounding Frequency, as it affects the calculation of interest accrual, and incorrect frequencies can lead to incorrect interest charges, such as the 2015 Ally Bank auto loan scandal.
• Fees and Charges, as they affect the total amount to be repaid, and incorrect fees can lead to overcharging or undercharging, such as the 2013 Bank of America mortgage settlement.

Common Gaps

People often overlook or take for granted the Assumption of Equal Payments, which can lead to incorrect amortization schedules if the payments are not equal, such as in the case of adjustable-rate loans or loans with changing payment frequencies, and this assumption can cause significant errors in the calculation of the principal and interest portions of each payment.