@Mike9241 wrote:
unless there is something you are not mentioning the tax basis to your sister is 50% of the Fair Market Value on the date your last parents died + any improvements she made.
Per the taxpayer, he bought out his sister several months before selling. While the two of them may have paid less capital gains tax had they sold the property while the sister was still a co-owner, it seems that ship has sailed.
Taxpayer's basis is half the FMV on the date of the parent's death plus whatever he paid for his sister's share.
