Amortization Table

An amortization table provides a row-by-row breakdown of every scheduled payment over the life of a loan, showing the payment number, total payment amount, interest portion, principal portion, and remaining unpaid principal balance (UPB) after each installment. For mortgage note investors, the amortization table is one of the most practical tools in the due diligence toolkit — it reveals exactly where a loan sits in its repayment lifecycle, how much principal has actually been retired, and how the balance will decline over the remaining term.

Structure of an Amortization Table

A standard amortization table for a fully amortizing fixed-rate mortgage contains five columns. Here is a simplified example for a $100,000 loan at 6.0% interest over 30 years (360 monthly payments of $599.55):

The pattern is clear: early payments are heavily weighted toward interest, with the proportion shifting gradually toward principal over time. At payment #1, only $99.55 goes to principal; by payment #300, it is $423.93. This front-loading of interest is why borrowers who sell or refinance within the first few years of a 30-year mortgage have barely reduced their balance.

Why Note Investors Use Amortization Tables

When evaluating a performing loan, the amortization table answers several critical questions:

• Where is the loan in its lifecycle? A loan that is 10 years into a 30-year term has already passed through the steepest interest portion. Remaining payments will retire principal more aggressively, which affects yield calculations if you buy at a discount.
• What is the projected cash flow? The table gives you exact payment-by-payment figures for modeling cash-on-cash return and net present value.
• Does the actual UPB match the table? Comparing the amortization table against the borrower's real payment history can reveal missed payments, partial payments, or misapplied funds. If the current UPB on the data tape is higher than what the table projects for a given payment number, the loan has a payment gap somewhere.
• How does a modification change the economics? When restructuring a non-performing loan through a loan modification, investors generate a new amortization table reflecting the modified rate, term, or principal reduction to evaluate whether the workout makes financial sense.

Amortization Tables for Non-Standard Loans

Not every loan follows the clean pattern above. Several common structures produce different table shapes:

• Interest-only loans — The table shows zero principal reduction during the interest-only period. An interest-only mortgage with a 10-year IO period followed by 20 years of amortization will show a flat balance for 120 payments, then accelerated principal reduction over the remaining 240.
• Balloon mortgages — A balloon mortgage amortizes on a longer schedule (often 30 years) but requires full repayment at a much earlier maturity date. The amortization table runs for the full theoretical term, but the borrower owes the entire remaining balance as a lump sum when the balloon comes due.
• Adjustable-rate mortgages — An ARM produces a table that resets at each adjustment period. The interest and principal split changes not just from the natural amortization curve but also from rate changes, making the table more complex to project.

Practical Application

Experienced note investors do not just read amortization tables — they build them. A simple spreadsheet or financial calculator can generate a table for any combination of principal balance, interest rate, and remaining term. When pricing a performing note at a discount, the investor overlays the amortization table with their purchase price to calculate yield. When negotiating a modification on a defaulted loan, the investor builds a new table to ensure the modified terms produce an acceptable return. The amortization table turns abstract loan terms into concrete, payment-level economics that drive every buy, hold, and exit decision.