After my dad passed away in 2011, the ownership of our home in India, which was built in 1980, was transferred to my mom. In January 2015, my mom added me and my brother to the title. (It was implicit that both of us would inherit our home some day.) Now there are three legal owners with equal claim to the property. We sold the property in June 2019 and proceeds were equally distributed among the three of us. My brother and I had left India in early 1990s and are US citizens. We continue to work in the US. My mom is not a US citizen. We did pay taxes in India after the transaction. Now, what is the cost basis of our home for me and my brother, price of the home in 1980 or in 2015, when we became legal owners?