BUSDAYNTH

BUSDAYNTH(iYear, iMonth, iNoOfDays)
Returns the nth business day in a particular month and year.

REMARKS
* You can use the built-in WORKDAY.INTL function to return the date serial number that is a given number of working days before or after a date.
* You can use the user defined BUSDAYNEXT function to
* You can use the user defined BUSDAYPREVIOUS function to
* You can use the user defined BUSDAYMONTHSTART function to
* You can use the user defined BUSDAYMONTHEND function to
* You can use the user defined BUSDAYYEARSTART function to
* You can use the user defined BUSDAYYEAREND function to
* You can use the user defined BUSDAYSADD function to
* You can use the user defined BUSDAYDIFF function to

Public Function BUSDAYNTH( _ 
         ByVal iYear As Integer, _ 
         ByVal iMonth As Integer, _ 
         ByVal iNoOfDays As Integer) _ 
         As Date 

Dim dtFirstDayOfMonth As Date 
Dim dtLastDayPreviousMonth As Date 

   dtFirstDayOfMonth = Application.WorksheetFunction.Date(iYear, iMonth, 1) 
   dtLastDayPreviousMonth = dtLastDayOfYear - 1 

   BUSDAYNTH = Application.WorksheetFunction.WorkDay_Intl(dtLastDayPreviousMonth, iNoOfDays) 
End Function 

For instructions on how to add this function to a workbook refer to the page under Inserting Functions