PPmt(n1, n2, n3, n4, n5)
n1, n2, or n3 are negative or 0.
Either n4 or n5 is negative.
If any parameter is null, the function returns null. If the payment amount (n3) is less than the monthly interest load, the function returns 0.
261.6160716858, which is the amount of principal repaid on a $30,000 loan at 8.5% for the three months between the seventh month and the tenth month of the loan’s term.
4656.19166430515, which is the amount of principal repaid during the third year of the loan.
0, because in this case the monthly payment is less than the interest the loan accrues during the month, therefore, no part of the principal is repaid.

PPmt