Sidney Crosby and his unmarried partner, Kathy Leutner, decided to buy a new house just outside of Pittsburg, Pennsylvania. After much searching, they find their dream home and buy it for $2.2 million. They put a down payment of $700,000 on the house and finance the other $1.5 million. Each takes out a $750,000 mortgage, for a total of $1.5 million.

1. Since they are unmarried, can each deduct the full mortgage interest on their tax returns or are they limited by the mortgage interest limitations of IRC 163(h)(3)(B)? Is the mortgage interest limit on acquisition indebtedness applied on a per residence or per taxpayer basis?
2. Can you locate a Chief Counsel Advice (CCA) that deals with this situation? Give the CCA citation and determine if it answers the above question.
3. Did you find any other primary authority dealing with this issue (such as a court case, an IRS Action on Decision (AOD), etc.? If so, what did you find?