After you file

No, the mutual fund had been owned by my father in  law.  I have taken over his brokerage account in early 2018 due to his advanced age and dementia.  The only paperwork we have is a quantity from reinvested dividends in 99, (and 1099's from 2004-2018)  and going backwards realizing we have no information on 80X.XX shares.  So we need to establish the basis.  It would be different with inheritance since the basis is the same date as an inheritance. To further complicate The original brokerage is gone, the second brokerage has been sold, and we transferred from the 3rd to another.