Contributions made to a participant’s retirement account from assets that have already been subject to income tax. For Traditional IRAs, these are referred to as nondeductible contributions. For qualified plans, such as 401(k) plans, and 403(b) plans, these are referred to as after-tax contributions.
After-tax balances are also referred to as ‘basis’
Additional Helpful Information
For any year that an individual makes nondeductible contributions he/she should file IRS Form 8606.
Form 8606 helps the individual to track the after tax/nondeductible amount so that it is not taxed when distributed from the traditional IRA.
Form 8606 must also be filed for any distributions that occur , beginning the year the after-tax/nondeductible amount is credited to the traditional IRA, until all the basis is distributed. This helps to determine the non-taxable portion of the distribution.
The basis recovery rule under IRC § 72(e)(8) provides for pro-rata distributions of pre-tax and post-tax amounts. Except for pre-1987 accrued balances, distributions from a plan, where the participant’s balance includes after-tax amounts, must include a pro-rated amount of pre-tax and post-tax balance. Where balances accrued pre-1987, the participant may choose to withdraw only the after-tax balance of that amount.
See Form 8606 for more information