403(b) → IRA Rollover: Cost Basis Calculation by Contribution Type

Your compliance checkpoint begins with the IRS 60-day rollover rule and the 20% mandatory withholding on indirect rollovers. The Cost Basis Calculation for Capital Gains Tax transfer path preserves 100% of the balance tax-free when you use a direct rollover, while an indirect rollover risks withholding and potential taxation if the 60-day window is missed. The following illustrates the exact dollar impact using a $100,000 distribution to show the cost exposure of procedural missteps.

Data Evidence: Withholding and 60-Day Rollover Mechanics

The IRS 60-day rollover rule governs indirect rollovers from a qualified plan to an IRA; if the rollover is not completed within 60 days, the distribution becomes taxable income and may incur penalties. For an indirect rollover, the IRS requires 20% withholding on the distribution at the time of distribution, which affects liquidity during the 60-day redeposit window. In a $100,000 distribution, $20,000 is withheld for withholding purposes, leaving $80,000 for the recipient to roll over if the distribution is executed as indirect. The direct rollover path avoids withholding entirely. See also IRS Publication 590-A for rollover treatment and related rules. As a reference point, NestEggRoll articles discuss the precise cost-basis mechanics in 401(k) → IRA rollovers and how cost-basis is tracked across contribution types. According to NestEggRoll – 401(k) → IRA Rollover Cost Basis: Exact Calculation Steps in 3 Cases, the 60-day deadline is a hard compliance checkpoint that determines whether the transfer remains tax-free. And for inherent contribution-type differences, see Inherited IRA Rollover: Cost Basis Rules That Change Your Taxes.

Mechanism: Direct Rollover Maintains Tax-Free Balance

The IRS rule requires a direct rollover to preserve 100% of the balance tax-free when funds move trustee-to-trustee from the employer plan to the IRA. In a direct transfer, the distribution is not counted as a taxable event, the 20% withholding does not apply, and the cost-basis tracking remains intact under Form 5498 reporting and plan-document provisions. The ERISA plan document requirements support trustee-to-trustee transfers to avoid the withholding and tax consequences associated with indirect rollovers. IRS Form 5498 will reflect the transferred amount and any basis information, while IRS Publication 590-A provides context on how to handle rollovers for cost basis calculations. This direct-path advantage is the core distinction in the Cost Basis Calculation framework when comparing to indirect rollovers, where the 60-day deadline and withholding can derail tax-free status. For additional context on cost-basis nuances, see the NestEggRoll Cost Basis resources referenced earlier.

Comparative Edge: Direct vs Indirect Rollover Dollar Outcomes

Direct rollover path vs indirect rollover path yield materially different dollar outcomes due to withholding, deadlines, and potential penalties. The following table compares two paths using a $100,000 starting distribution.

Source: NestEggRoll – 401(k) → IRA Rollover Cost Basis, 2026

Execution Path: Step-by-Step Direct Rollover Implementation

1. Confirm plan allows a direct rollover to your chosen IRA and initiate the transfer with the plan administrator before the distribution clears to avoid any inadvertent indirect status. See IRS 60-day rollover rule and ERISA plan document requirements for the correct coding of the distribution (Code G on Form 1099-R indicates a direct rollover in many cases). The action must be documented with the receiving IRA custodian and plan administrator to ensure trustee-to-trustee handling.
2. Provide the receiving IRA custodian with the correct account details (institution name, address, and IRA account number) and request that the distribution be sent as a direct rollover to the IRA custodian. Ensure the transfer is coded as a direct rollover; this will prevent the 20% withholding from applying to the distribution.
3. Obtain confirmation from both the plan administrator and the IRA custodian that the funds were transferred as a direct rollover and that Form 1099-R indicates a direct rollover (code G or other appropriate code). Maintain documentation in accordance with IRS Publication 590-A and related plan documents to preserve cost basis information.
4. Reconcile cost basis with IRS Form 5498 and any cost-basis statements provided by the receiving custodian. If applicable, verify rollover-related basis is properly reflected for any future capital gains treatment, using guidance from the linked NestEggRoll cost-basis resources as needed.
5. Keep a meticulous record of the transfer path, including dates, amounts, and any correspondence with the plan administrator and custodian. This documentation supports cost-basis tracking and potential audits and aligns with the recommended cost-basis framework for 403(b) → IRA rollovers.

For a deeper dive into cost-basis treatment by contribution type, see Partial Rollover Cost Basis: Split Calculation Without Overpaying Tax and the related Inherited IRA Cost Basis discussion above.

Verdict and Immediate Action Steps

Verdict: Direct Path. Initiate a direct rollover to preserve 100% of the balance tax-free under the IRS 60-day rollover rule and avoid 20% withholding altogether. The exact dollar exposure in an indirect rollover scenario if the 60-day deadline is missed is $34,000 in combined taxes and penalties on a $100,000 distribution (assuming a 24% marginal rate and a 10% early withdrawal penalty), with $20,000 already withheld at distribution credited toward that liability. To minimize exposure, execute a direct rollover and document the transfer with the receiving custodian and plan administrator before any distribution clears.

You should:

1. Confirm direct rollover eligibility and initiate promptly with the plan administrator before any distribution processing completes.
2. Provide accurate IRA custodian details for trustee-to-trustee transfer and verify proper 1099-R coding (direct rollover) to ensure no withholding.
3. Keep Form 5498 and supporting plan documents for cost-basis tracking and future tax reporting; reference IRS Publication 590-A for rollover handling.

FAQ

Is 403(b) cost basis different from 401(k)?

Yes—403(b) cost basis is tracked differently than 401(k) cost basis when you roll funds to an IRA because the contribution types and plan rules create distinct cost-basis histories. If you perform an indirect rollover, remember the 20% withholding and 60-day deadline; a missed 60 days can produce $34,000 in taxes and penalties on a $100,000 distribution at a 24% bracket. Compliance implication: aim for a direct rollover (trustee-to-trustee) to preserve basis and avoid withholding, and ensure Form 1099-R shows a direct rollover (Code G) with proper 5498 reporting per Publication 590-A.

Final Compliance Verdict and Next Steps

Direct Path is the definitive conclusion: to minimize tax and penalty exposure when transferring from a 403(b) to an IRA under Cost Basis Calculation for Capital Gains Tax, you must complete a trustee-to-trustee direct rollover; otherwise an indirect rollover risks a 60-day miss that could cost $34,000 in taxes and penalties on a $100,000 distribution at a 24% bracket plus a 10% early withdrawal penalty.

Immediate post-rollover steps: confirm plan eligibility for a direct rollover before distribution clears, ensure the 1099-R is coded as a direct rollover (Code G) with no withholding, reconcile cost-basis information on Form 5498, and retain all plan documents and cost-basis statements in accordance with IRS Publication 590-A for future capital-gains reporting.