$150,000 in 2012 1/3 of this is your inherited tax basis for this portion is $50K
$250,000 in 2017 if there were 3 owners - you, grandma, and a 3rd party and grandma left her 1/3 in equal portions to 6 people including you your inherited tax basis in her portion would be 1/6 of 1/3 or about $13,889
*you would not own 50%
* with 3 equal owners in 2017 including you each owns 1/3 so that means before we figure the allocation of grandma's share 2/3 (grandma 1/3 others 1/3) would not be owned by you.
1/6 of 1/3 of grandma's share that you inherited would be 5.56% so you would own 38.89%
*others own 27.78% of grandma's share (5/6 of 1/3) and 33.33% directly from when your father passed or 61.11%
I went through the math just to make sure I understood the ownership %'s correctly.
