if you intend for joint ownership, you have a partnership. a partnership is supposed to file its own annual tax return with penalties for failure to file. if a partnership then, the title to the property should be in the partnership's name and the mortgage will also be in the partnerships name. there's a good reason for this.
One of the basic rules of income taxes is that the person paying the expense gets the deduction, and the mortgage interest deduction is no exception. If you and another person pay the mortgage, you can each take a deduction only for the amount of mortgage interest that you actually pay, assuming you meet the other requirements. For example if the total mortgage payments for the year are $10,000, and you pay only $4,000, you can deduct only 40 percent of the mortgage interest, even if the other person agrees to let you claim his portion. This applies not only to unmarried individuals, but to married couples who file separate returns.
this doesn't become an issue when the property and mortgage are in the name of the partnership, because it is the partnership paying the mortgage not the individuals. but say the partnership is short of cash when a payment is due. the wise thing to do would be for each partner to put money into it and have it pay the mortgage rather than each sending personal payments to the mortgage company
if only your name was on the mortgage, and it went into default, if there was a balance after the sales proceeds were applied, if the mortgage company could come after anyone it would be only you.
if you were the only one on the title and mortgage, it might be possible to sell the property without your "partner's" okay and walk off with the net proceeds. he might sue, but without the proper paperwork, I don't think he wouldn't stand a chance
I'm an accountant, but I've seen many things happen that turned out badly for at least one of the "partner's" in the course of practicing for over 40 years. a written partnership agreement would be a good idea. without one if you or your partner go to court of the actions of the other it's going to be resolved by whom the judge believes. Suppose he's to come up with his cash for the venture when needed but doesn't. What recourse do you have?.
I'm not a lawyer and laws vary from state to state, so you should probably consult one to best structure the arrangement.
