The Excel COUPDAYBS Function

Related Functions:

Function Description

The Excel Coupdaybs function calculates the number of days from the beginning of a coupon's period to the settlement date.

The syntax of the function is:

COUPDAYBS( settlement, maturity, frequency, [basis] )

Where the arguments are as follows:

settlement

The settlement date of the security.

maturity

The maturity date of the security.

frequency

An integer, representing the number of coupon payments per year. This must have the value 1, 2, or 4, meaning:

1	-	Annually
2	-	Semi-Annually
4	-	Quarterly

[basis]

An optional integer argument that specifies the day count basis to be used.

This must be one of the following values:

Basis	Day Count Basis
0 (or omitted)	US (NASD) 30/360
1	actual/actual
2	actual/360
3	actual/365
4	European 30/360

The financial day count basis rules are explained on the Wikipedia Day Count Convention page

Note that the settlement and maturity dates should be input as either:

References to cells containing dates

Dates returned from formulas.

Warning: If you attempt to input these dates as text, there is a chance that Excel may misinterpret them due to different date systems, or date interpretation settings on your computer.

Excel Coupdaybs Function Example

Cell A3 of the spreadsheet below contains an example of the Excel Coupdaybs function, used to calculate the number of days from the beginning of a coupon's period to the settlement date. The security has the settlement date 01-Jan-2011, the maturity date 25-Oct-2012, and 4 payments per year. The US (NASD) 30/360 day count basis is used.

Formulas:

	A
1	01-Jan-2011
2	25-Oct-2012
3	=COUPDAYBS( A1, A2, 4 )

Results:

	A
1	01-Jan-2011
2	25-Oct-2012
3	66

Note that, in the above example:

As recommended, the date arguments have been input as references to cells containing dates;
As the [basis] argument has been omitted, the function uses the default value 0 (denoting the US (NADS) 30/360 day count basis).

For further details and examples of the Excel Coupdaybs function, see the Microsoft Office website.

Coupdaybs Function Errors

If you get an error from the Excel Coupdaybs Function, this is likely to be one of the following:

Common Errors

#NUM!

Occurs if either:

The supplied settlement date is ≥ maturity date;
The supplied frequency argument is a number that is not equal to 1, 2 or 4;
The supplied [basis] argument is a number that is not equal to 0, 1, 2, 3 or 4.

#VALUE!

Occurs if either:

The supplied settlement or the supplied maturity dates are not a valid Excel dates;
Any of the supplied arguments are non-numeric.

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