We jointly own (not "co-own") a property, thus are each liable for the full amount of the loan. How do I answer "your share of the outstanding mortgage principal"?

[kathleenosullivan]

We split the mortgage interest deduction 50-50.  That is not the question.  Given joint ownership, is my share of the outstanding mortgage principal all or half?

[LeeM · Accepted solution]

Your share of the outstanding mortgage principal would only be 1/2 and that is what you should report when asked (since you are still considered, as of now, to be responsible for 50% and are only deducting 50% of the interest).