Have a Tax Question? Ask a Tax Expert
As your mother made a gift of the property when you all were placed as owners, your cost is the same as her cost plus improvements. Had you inherited after her passing, you would have received a step up in cost on the day she passed away.You each report 1/6 of the cost (your mother's basis plus improvements she made or you made after ownership changed).How your mother acquired is important. If she inherited (even half) her cost (basis) would be the value when that person passed away.Gain is the difference in basis and sale (less cost to sale).
How did your mother acquire the property?
If you can answer my question, I can advise further.