the inteterst rate on an auto loan im may was 12 3/8%. by september the rate was up to 14 1/4%. how many percentage points did the interest rate increase over the period?
I am not certain your meaning of "points".
Basis Points: 100 points is equal to 1 percentage place
Points: Equal to 1% of loan
So the answer to your question is either
Points: 14.250-13.375
Basis Points: 1425.0-1337.5