After-tax IRA basis
Inherited IRA Basis and Form 8606
After-tax basis in a traditional IRA can carry to the beneficiary and make part of inherited distributions nontaxable. The beneficiary needs the owner’s Form 8606 records to calculate and report that amount.
What to know first
- The owner’s unrecovered nondeductible contribution basis does not simply disappear at death.
- Ask for prior Forms 8606 and contribution records before taking distributions.
- The taxable and nontaxable shares are generally determined under the Form 8606 pro-rata rules.
- Inherited IRA basis is account-specific work that should be reconciled before filing.
Find the decedent’s basis records
Form 8606 tracks nondeductible traditional IRA contributions and basis that has not yet been recovered. Custodian statements often show balances and distributions but may not show tax basis.
Request the owner’s prior returns, Forms 8606, and contribution documentation. Without those records, a beneficiary may overstate taxable income or be unable to substantiate a nontaxable portion.
Report the beneficiary distribution
A Form 1099-R can show the taxable amount as undetermined. The beneficiary then uses the applicable Form 8606 calculation to divide a distribution between basis recovery and taxable income.
Do not assume the full payment is tax-free because the owner made nondeductible contributions. Basis usually comes out proportionally rather than first, and inherited accounts can require special coordination.
Model your inherited IRA deadline
Use the inherited IRA calculator to compare the 10-year rule, annual beneficiary RMDs, and eligible designated beneficiary schedules.
Open the inherited IRA calculatorFrequently asked questions
Does an IRA custodian track Form 8606 basis?
Usually not. The taxpayer is responsible for maintaining Form 8606 and supporting records for nondeductible contributions.
Is an inherited Roth IRA reported on Form 8606?
Form 8606 can apply to certain Roth IRA distributions, but most qualified inherited Roth distributions are tax-free. Review the five-year rule and the form instructions for the specific payment.
Sources
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