Actual/Actual

Detailed Description of Actual/Actual

The Actual/Actual method is considered the most mathematically accurate way to calculate interest because it accounts for the specific calendar nuances of every month and year. While other methods rely on standardized assumptions, Actual/Actual reflects the true passage of time.

To calculate interest using this method, the lender follows these steps:

• The annual interest rate is divided by the actual number of days in the year (365 or 366) to find the daily interest rate.
• This daily rate is then multiplied by the actual number of days in the current billing cycle.
• The resulting figure is multiplied by the outstanding principal balance to determine the interest payment due.

There are several key characteristics that distinguish Actual/Actual from other common commercial lending conventions:

• Precision: Unlike the 30/360 convention, which assumes every month has 30 days regardless of its actual length, Actual/Actual recognizes that February is shorter and months like August and October are longer.
• Leap Year Adjustment: During a leap year, the denominator in the calculation shifts to 366. This ensures that the borrower is not overcharged or undercharged based on the extra day in February.
• Comparison to Actual/360: Many commercial bank loans use an Actual/360 convention, which uses the actual days in a month but divides by a 360-day year. Because the denominator is smaller in an Actual/360 calculation, the borrower effectively pays about 5 to 6 days of "extra" interest per year compared to the Actual/Actual method. Therefore, Actual/Actual is generally more favorable for the borrower.
• Market Usage: Actual/Actual is frequently used in agency lending, particularly with Government-Sponsored Enterprise (GSE) loans such as those from Fannie Mae and Freddie Mac. It is also the standard for U.S. Treasury bonds and many long-term fixed-rate commercial products.

For a commercial real estate investor, the choice of day count convention can impact the total cost of capital over the life of the loan. While the difference in a single month may seem negligible, on a multi-million dollar commercial mortgage, the Actual/Actual method can result in significant savings over a 10 or 30-year term when compared to the Actual/360 method.