What Is an Amortization Schedule?

Amortizing loans feature level payment amounts over the life of the loan, but with varying proportions of interest and principal making up each payment. A traditional mortgage is a prime example of such a loan.

A loan amortization schedule represents the complete table of periodic loan payments, showing the amount of principal and interest that comprise each level payment until the loan is paid off at the end of its term. Early in the schedule, the majority of each payment goes toward interest; later in the schedule, the majority of each payment begins to cover the loan’s remaining principal.

Understanding an Amortization Schedule

If you are taking out a mortgage or auto loan, your lender should provide you with a copy of your loan amortization schedule so you can see at a glance what the loan will cost and how the principal and interest will be broken down over its life.

In a loan amortization schedule, the percentage of each payment that goes toward interest diminishes a bit with each payment and the percentage that goes toward principal increases. Take, for example, a loan amortization schedule for a $165,000, 30-year fixed-rate mortgage with a 4.5% interest rate:

Amortization schedules can be customized based on your loan and your personal circumstances. With more sophisticated amortization calculators, like the templates you can find in Excel you can compare how making accelerated payments can accelerate your amortization. If for example, you are expecting an inheritance, or you get a set yearly bonus, you can use these tools to compare how applying that windfall to your debt can affect your loan’s maturity date and your interest cost over the life of the loan.

In addition to mortgages, car loans and personal loans are also amortizing for a term set in advance, at a fixed interest rate with a set monthly payment. The terms vary depending on the asset. Most conventional home loans are 15- or 30-year terms. Car owners often get an auto loan that will be repaid over five years or less. For personal loans, three years is a common term.

Formulas Used in Amortization Schedules

Borrowers and lenders use amortization schedules for installment loans that have payoff dates that are known at the time the loan is taken out, such as a mortgage or a car loan. There are specific formulas that are used to develop a loan amortization schedule. These formulas may be built into the software you are using, or you may need to set up your amortization schedule from scratch.

If you know the term of a loan and the total periodic payment amount, there is an easy way to calculate a loan amortization schedule without resorting to the use of an online amortization schedule or calculator. The formula to calculate the monthly principal due on an amortized loan is as follows:

Principal Payment = Total Monthly Payment – [Outstanding Loan Balance x (Interest Rate / 12 Months)]

To illustrate, imagine a loan has a 30-year term, a 4.5% interest rate, and a monthly payment of $1,266.71. Starting in month one, multiply the loan balance ($250,000) by the periodic interest rate. The periodic interest rate is one-twelfth of 4.5% (or 0.00375), so the resulting equation is $250,000 x 0.00375 = $937.50. The result is the first month’s interest payment. Subtract that amount from the periodic payment ($1,266.71 – $937.50) to calculate the portion of the loan payment allocated to the principal of the loan’s balance ($329.21).

To calculate the next month’s interest and principal payments, subtract the principal payment made in month one ($329.21) from the loan balance ($250,000) to get the new loan balance ($249,670.79), and then repeat the steps above to calculate which portion of the second payment is allocated to interest and which is allocated to the principal. You can repeat these steps until you have created an amortization schedule for the full life of the loan.

An Easier Way to Calculate an Amortization Schedule

Calculating an amortization schedule is as simple as entering the principal, interest rate, and loan term into a loan amortization calculator. But you can also calculate it by hand if you know the rate on the loan, the principal amount borrowed, and the loan term.

How to Calculate the Total Monthly Payment

Typically, the total monthly payment is specified by your lender when you take out a loan. However, if you are attempting to estimate or compare monthly payments based on a given set of factors, such as loan amount and interest rate, you may need to calculate the monthly payment as well.

If you need to calculate the total monthly payment for any reason, the formula is as follows:

Total Monthly Payment = Loan Amount [ i (1+i) ^ n / ((1+i) ^ n) – 1) ]

where:

• i = monthly interest rate. You’ll need to divide your annual interest rate by 12. For example, if your annual interest rate is 6%, your monthly interest rate will be .005 (.06 annual interest rate / 12 months).
• n = number of payments over the loan’s lifetime. Multiply the number of years in your loan term by 12. For example, a 30-year mortgage loan would have 360 payments (30 years x 12 months).

Using the same example from above, we will calculate the monthly payment on a $250,000 loan with a 30-year term and a 4.5% interest rate. The equation gives us $250,000 [(0.00375 (1.00375) ^ 360) / ((1.00375) ^ 360) – 1) ] = $1,266.71. The result is the total monthly payment due on the loan, including both principal and interest charges.

30-Year vs. 15-Year Amortization Table

If a borrower chooses a shorter amortization period for their mortgage—for example, 15 years—they will save considerably on interest over the life of the loan, and they will own the house sooner. That’s because they’ll make fewer payments for which interest will be amortized. Additionally, interest rates on shorter-term loans are often at a discount compared to longer-term loans.

There is a tradeoff, however. A shorter amortization window increases the monthly payment due on the loan. Short amortization mortgages are good options for borrowers who can handle higher monthly payments without hardship; they still involve making 180 sequential payments (15 years x 12 months).

It’s important to consider whether or not you can maintain that level of payment based on your current income and budget.

Using an amortization calculator can help you compare loan payments against potential interest savings for a shorter amortization to decide which option suits you best. Here’s what a $500,000 loan with a 6% interest rate would look like, with a hypothetical 30-year and 15-year schedule to compare:

What Is the 11th District Cost of Funds Index?

The 11th District Cost of Funds Index (COFI) is a monthly weighted average of the interest rates paid on checking and savings accounts offered by financial institutions operating in Arizona, California, and Nevada. It is one of many indices used by mortgage lenders to adjust the interest rate on adjustable rate mortgages (ARM) and was launched in 1981. With an ARM mortgage, the interest rate on a mortgage moves up and down along with some standard interest rate chosen by the lender, and COFI is one of the most popular indices in the western states.

Published on the last day of each month, the COFI represents the cost of funds for western savings institutions that are members of Federal Home Loan Bank of San Francisco, a self-regulatory agency, and satisfy the Bank’s criteria for inclusion in the index.

Understanding the 11th District COFI

The 11th District Cost of Funds Index (COFI) is computed using several different factors, with interest paid on savings accounts comprising the largest weighting in the average. As a result, the index tends to have low volatility and follow market interest rate changes somewhat slowly; it is generally regarded as a two-month lagging indicator of market interest rates. The interest rate on a mortgage will not match the COFI, rather the ARM rate is typically 2% to 3% higher than COFI, depending on the borrower’s credit history, the size and terms of the loan, the ability of the borrower to negotiate with the bank and many other factors.

Because it is computed using data from three western states, the COFI is primarily used in the western U.S., while the 1-year Treasury index is the measure of choice in the eastern region. On April 30, the Federal Home Loan Bank of San Francisco announced the COFI for March 2018 of 0.814%, slightly lower than February.

What Is an Asset-Backed Security (ABS)?

An asset-backed security (ABS) is a type of financial investment that is collateralized by an underlying pool of assets—usually ones that generate a cash flow from debt, such as loans, leases, credit card balances, or receivables. It takes the form of a bond or note, paying income at a fixed rate for a set amount of time, until maturity. For income-oriented investors, asset-backed securities can be an alternative to other debt instruments, like corporate bonds or bond funds.

Understanding Asset-Backed Securities (ABSs)

Asset-backed securities allow their issuers to raise cash, which can be used for lending or other investment purposes. The underlying assets of an ABS are often illiquid and can’t be sold on their own. So, pooling assets together and creating a financial instrument out of them—a process called securitization—allows the issuer to make illiquid assets marketable to investors. It also allows them to get shakier assets off their books, thus alleviating their credit risk.

The underlying assets of these pools may be home equity loans, automobile loans, credit card receivables, student loans, or other expected cash flows. Issuers of ABSs can be as creative as they desire. For example, asset-backed securities have been built based on cash flows from movie revenues, royalty payments, aircraft landing slots, toll roads, and solar photovoltaics. Just about any cash-producing vehicle or situation can be securitized into an ABS.

For investors, buying an ABS affords the opportunity of a revenue stream. The ABS allows them to participate in a wide variety of income-generating assets, sometimes (as noted above) exotic ones that aren’t available in any other investment.

How an Asset-Backed Security Works

Assume that Company X is in the business of making automobile loans. If a person wants to borrow money to buy a car, Company X gives that person the cash, and the person is obligated to repay the loan with a certain amount of interest. Perhaps Company X makes so many loans that it starts to run out of cash. Company X can then package its current loans and sell them to Investment Firm X, thus receiving the cash, which it can then use to make more loans.

Investment Firm X will then sort the purchased loans into different groups called tranches. These tranches contain loans with similar characteristics, such as maturity, interest rate, and expected delinquency rate. Next, Investment Firm X will issue securities based on each tranche it creates. Similar to bonds, each ABS has a rating indicating its degree of riskiness—that is, the likelihood the underlying loans will go into default.

Individual investors then purchase these securities and receive the cash flows from the underlying pool of auto loans, minus an administrative fee that Investment Firm X keeps for itself.

Special Considerations

An ABS will usually have three tranches: class A, B, and C. The senior tranche, A, is almost always the largest tranche and is structured to have an investment-grade rating to make it attractive to investors.

The B tranche has lower credit quality and, thus, has a higher yield than the senior tranche. The C tranche has a lower credit rating than the B tranche and might have such poor credit quality that it can’t be sold to investors. In this case, the issuer would keep the C tranche and absorb the losses.

Types of Asset-Backed Securities

Theoretically, an asset-based security (ABS) can be created out of almost anything that generates an income stream, from mobile home loans to utility bills. But certain types are more common. Among the most typical ABS are:

Collateralized Debt Obligation (CDO)

A CDO is an ABS issued by a special purpose vehicle (SPV). The SPV is a business entity or trust formed specifically to issue that ABS. There are a variety of subsets of CDOs, including:

• Collateralized loan obligations (CLOs) are CDOs made up of bank loans.
• Collateralized bond obligations (CBOs) are composed of bonds or other CDOs.
• Structured finance-backed CDOs have underlying assets of ABS, residential or commercial mortgages, or real estate investment trust (REIT) debt. 
• Cash CDOs are backed by cash-market debt instruments, while other credit derivatives support synthetic CDOs.
• Collateralized mortgage obligations (CMOs) are composed of mortgages—or, more precisely, mortgage-backed securities, which hold portfolios of mortgages (see below).

Though a CDO is essentially structured the same as an ABS, some consider it a separate type of investment vehicle. In general, CDOs own a wider and more diverse range of assets—including other asset-based securities or CDOs.

Home Equity ABS

Home equity loans are one of the largest categories of ABSs. Though similar to mortgages, home equity loans are often taken out by borrowers who have less-than-stellar credit scores or few assets—the reason they didn’t qualify for a mortgage. These are amortizing loans—that is, payment goes towards satisfying a specific sum and consists of three categories: interest, principal, and prepayments.

Auto Loan ABS

Car financing is another large category of ABS. The cash flows of an auto loan ABS include monthly interest payments, principal payments, and prepayments (though the latter is rarer for an auto loan ABS is much lower when compared to a home equity loan ABS). This is another amortizing loan.

Credit Card Receivables ABS

Credit card receivables—the amount due on credit card balances—are a type of non-amortizing asset ABS: They go to a revolving line of credit, rather than towards the same set sum. So they don’t have fixed payment amounts, while new loans and changes can be added to the composition of the pool. The cash flows of credit card receivables include interest, principal payments, and annual fees.

There is usually a lock-up period for credit card receivables where no principal will be paid. If the principal is paid within the lock-up period, new loans will be added to the ABS with the principal payment that makes the pool of credit card receivables staying unchanged. After the lock-up period, the principal payment is passed on to ABS investors.

Student Loan ABS

ABSs can be collateralized by either government student loans, guaranteed by the U.S. Dept. of Education, or private student loans. The former have had a better repayment record, and a lower risk of default.

An ABS will usually have three tranches: class A, B, and C. The senior tranche, A, is almost always the largest tranche and is structured to have an investment-grade rating to make it attractive to investors.

The B tranche has lower credit quality and, thus, has a higher yield than the senior tranche. The C tranche has a lower credit rating than the B tranche and might have such poor credit quality that it can’t be sold to investors. In this case, the issuer would keep the C tranche and absorb the losses.

The Bottom Line

Asset Backed Securities (ABS) are pools of loans that are packaged together into an investable security, which can in turn be bought by investors, predominantly large institutions, like hedge funds, insurance companies, and pension funds. ABS provide a method of diversification from typical bond mutual funds or individual bonds themselves. Most importantly, they are income generating assets, typically with a higher return than a normal corporate bond, all depending on the credit rating assigned to the ABS.

The underlying assets of an ABS could consist of auto loans, credit card receivables, and even more exotic investments, such as utility bills and toll roads. Such categories of ABS are referred to by different names such as CDO’s (Collateralized Debt Obligations), which are broken down into further sub-categories, such as CLO’s (Collateralized Loan Obligations). However, by far, the most popular and therefore liquid ABS are MBS (Mortgage Backed Securities), which provide an income stream from mortgage payments.

For the investor, ABS provide an income stream in line with the credit rating of the security, and offer an alternative to standard bond mutual funds.