This does not make sense to me. First, and IRA can only be left to an individual or split between individuals. Each person inheriting the IRA has to set up their inherited decedent IRA account. Was your Father in law over 70 !/2 at the time of his death? This has a bearing on the required minimum distribution (RMD). The rules are somewhat complex, but each person inheriting the IRA might be required to receive a RMD each year, either based on their own age and distribution rules, or, in reference to the age of the person who died. I don't know what you mean by "bases of estate"; but the RMD is a factor multiplied by the FMV of the IRA at December 31 of the prior year. Thus for 2017, the RMD would be the FMV of the IRA at 12/31/2016 multiplied by the factor for the individual who inherited the IRA.
**Disclaimer: Effort has been made to offer correct information; but due to the discussion forum limitations, the poster disclaims any legal responsibility for the accuracy of the poster's response**
