The COUPNCD function in Google Sheets calculates the next coupon date (i.e., the date when the next interest payment is due) for a security that pays periodic interest.

The function takes the following arguments:

settlement: The security's settlement date, which is the date on which the security is traded to the buyer. maturity: The security's maturity date, which is the date on which the security's face value will be repaid to the investor. frequency: The number of coupon payments per year. daycountconvention (optional): The day-count convention used to calculate the number of days between settlement and the next coupon date. This argument is typically omitted or set to 0, which indicates that the actual number of days should be used. The COUPNCD function returns a date value that represents the next coupon date for the security, which is the first coupon payment date after the settlement date. This function is commonly used in financial analysis to calculate the accrued interest for a bond or other fixed-income security.