Carmen’s current year individual return reports a $6,000 deduction for a questionable item not relating to a tax-shelter. Carmen does not make a disclosure regarding this item. The IRS audits Carmen’s return, and she consents to a deficiency. As a result, her tax liability increases from $20,000 to $21,860. Assume Carmen lacks substantial authority for the deduction.
a. What substantial understatement penalty (if any) will be imposed?
b. Will the penalty bear interest?
c. How would your answer to Parts a and b change if Carmen reported a $20,000 deduction instead of $6,000, and her tax liability increased by $6,200 to $26,200?