Names:

The name of this convention is 30/360 Bond Basis; Also known as

• 30A/360
• US (ISMA)

Computation Method:

The number of accrued days is calculated on the basis of a year of 360 days with 12 30-day months.
The year fraction is calculated as the number of accrued days divided by 360. Here is the general formula:

\[YearFraction = \frac{360*\left( Y_{2} - Y_{1}\right ) + 30*\left( M_{2} - M_{1}\right ) + \left( D_{2} - D_{1}\right )}{360} \]

Where:

\(Y_{1}\) is the year, expressed as a number, in which the first day of the calculation period falls;

\(Y_{2}\) is the year, expressed as a number, in which the day immediately following the last day included
in the calculation period falls;

\(M_{1}\) is the calendar month, expressed as a number, in which the first day of the calculation period falls;

\(M_{2}\) is the calendar month, expressed as a number, in which the day immediately following the last day included
in the calculation period falls;

\(D_{1}\) is the first calendar day, expressed as a number, of the calculation period or compounding period,
unless such number would be 31, in which case \(D_{1}\) will be 30;

\(D_{2}\) is the calendar day, expressed as a number, immediately following the last day included in the calculation period or compounding period,
unless such number would be 31 and \(D_{1}\) is 30 or 31, in which case \(D_{2}\) will be 30.