Grandfather passed away in 2000. All assets willed to grandmother. Grandmother passed away in 2007. All assets willed to father. Father passed away in August 2015. I am sole living heir.

As part of going through the estate, we discovered previously unknown stocks in grandfathers name. Stocks were able to be transferred to father's name, then cashed out as part of the estate in December 2015. Roughly about $15k total.

The question is, what is FMV basis of these stocks to which to estate must report capital gains? Again, they were transferred after father's death. Is it based off of grandmother's date of death? Grandfather's? Father's? Since the executor of the father's estate cashed out the stocks, my thinking is that we use his date as the basis point. But the accountant we are using (business manager, estate is not really his thing) is arguing that we have to use the grandfather's date as the basis.

Thoughts?