Is this reportable:  Father co-signed on a loan for his son for building lot. Two years later son sold the property for profit. Father never paid any money toward the property or loan. Because he was listed as a co-owner on the title, he received a 1099-S for half of the sales price. He also received a check for half of the proceeds. Is this a Capital gain with $0 cost basis? Or is the original purchase price split between the two of them as cost basis even though he paid $0?