Calculation of Margin (Debit) Interest

The formula to determine how margin interest is incurred is as follows:   Margin Interest = (Margin Debit * Margin Rate/360 days) * (Number of days the margin debit is carried) For example: $10,000 margin debit is charged a 8 ¾% margin rate for a period of 20 calendar days. Inserting the numbers in the formula above, the margin interest is calculated as follows:   (10,000 *8.34%/360) * 20 = $48.61 of margin interest charged to the account.