COUPNUM returns the numbers of coupons to be paid between the settlement and maturity dates, rounded up.
@settlement is the settlement date of the security.
@maturity is the maturity date of the security.
@frequency is the number of coupon payments per year.
@eom = TRUE handles end of month maturity dates special.
Allowed frequencies are: 1 = annual, 2 = semi, 4 = quarterly. 6 = bimonthly, 12 = monthly.
@basis is the type of day counting system you want to use:
0 MSRB 30/360 (MSRB Rule G33 (e))
1 actual days/actual days
2 actual days/360
3 actual days/365
4 European 30/360
5 European+ 30/360
If @frequency is other than 1, 2, or 4, COUPNUM returns #NUM! error. If @basis is omitted, MSRB 30/360 is applied. If @basis is not in between 0 and 4, #NUM! error is returned.