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When to file: the Apr 15 / Oct 15 windows

Two corrective windows exist for an excess contribution. April 15 of the year following the contribution is the timely-correction deadline; an automatic 6-month extension to October 15 applies ONLY if you timely-filed your original return (or Form 4868).

Last verified May 2026
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Which corrective window applies?

The §301.9100-2(b) auto-extension to Oct 15 only applies if the return (or Form 4868) was timely-filed.
After-deadline procedure (no §301.9100-2(b) extension)
IRC §4973

Apr 15, 2026 window has passed and no return / Form 4868 was timely-filed, so the §301.9100-2(b) automatic 6-month extension to Oct 15 does NOT apply. 6% excise applies for each year the excess remains. Options: withdraw excess (no NIA required) and file Form 5329, or carry forward / absorb in a future-year underage.

Selected issue: Roth IRA excess contribution. Procedure is the same NIA-based corrective distribution per §408(d)(4) for IRA / Roth and §223(f)(3) for HSA — but the tax year of inclusion differs: IRA NIA is taxable in the contribution year; HSA NIA is taxable in the year received (per §223(f)(3)).

The April 15 timely-correction window — verbatim statute

The statutory hook is IRC §408(d)(4):

“Paragraph (1) does not apply to the distribution of any contribution paid during a taxable year to an individual retirement account or for an individual retirement annuity if (A) such distribution is received on or before the day prescribed by law (including extensions of time) for filing such individual's return for such taxable year, (B) no deduction is allowed under section 219 with respect to such contribution, and (C) such distribution is accompanied by the amount of net income attributable to such contribution. Any net income described in subparagraph (C) shall be included in the gross income of the individual for the taxable year in which such contribution was made.”— 26 U.S.C. §408(d)(4) (read full statute)

The plain April 15 deadline applies if no extension was filed — “the day prescribed by law” for an individual return. Note that NIA on a returned IRA contribution is taxable in the year the contribution was made, not the year withdrawn — this is statute and matters for 1099-R coding.

The October 15 extension window — conditional

Treas. Reg. §301.9100-2(b) grants an automatic 6-month extension. Verbatim:

“An automatic extension of 6 months from the due date of a return excluding extensions is granted to make regulatory or statutory elections whose due dates are the due date of the return or the due date of the return including extensions provided the taxpayer timely filed its return for the year the election should have been made and the taxpayer takes corrective action as defined in paragraph (c) of this section within that 6-month extension period. This paragraph (b) does not apply to regulatory or statutory elections that must be made by the due date of the return excluding extensions.”— 26 CFR §301.9100-2(b) (read full regulation)

The IRS confirms this in Pub 590-A:

“If you timely filed your 2025 tax return without withdrawing a contribution that you made in 2025, you can still have the contribution returned to you within 6 months of the due date of your 2025 tax return, excluding extensions. If you do, file an amended return with "Filed pursuant to section 301.9100-2" written at the top.”— IRS Pub 590-A (2025), p. 35 (read publication)

The extension is automatic in two scenarios: (1) you filed Form 4868 on or before April 15, or (2) you filed your return on time. Both push the corrective deadline to October 15.

October 15 is NOT unconditional.Taxpayers who did not file by April 15 and did not file Form 4868 lose the extension — the regulation explicitly conditions the 6-month auto-extension on the taxpayer having “timely filed its return for the year the election should have been made.”

What changes at each deadline — calendar flow

The four dates that drive every excess-contribution decision in a given tax year T:

Apr 15 (T+1)
Timely-correction window closes.Last day to make a §408(d)(4) corrective distribution under the “day prescribed by law” without extension. After this date, the §301.9100-2(b) auto-extension only applies if you filed Form 4868 or filed your return on time.
May 31 (T+1)
Form 5498 received. Custodians must furnish Form 5498 (IRA contributions for tax year T) by May 31 of T+1 — i.e., AFTER April 15. If 5498 is the document that surfaces an excess, you may already be past the timely window before you knew.
Oct 15 (T+1)
Extended-correction window closes. Last day to make a §408(d)(4) corrective distribution under the §301.9100-2(b) automatic extension — only if your return for T was timely-filed (or Form 4868 was filed by April 15). After this date, NIA-based correction is no longer available.
Dec 31 (T)
§4973 excise base measured.The 6% excise on uncorrected excess is “determined as of the close of the taxable year” (statutory phrase) — if excess remains in the account on Dec 31 of year T, the 6% applies for that year (capped at 6% of the account's Dec 31 value).

The §4973 statutory anchor — verbatim

The excise tax language people shorthand as “uncorrected at year-end” is actually:

“In the case of [accounts/annuities listed], there is imposed for each taxable year a tax in an amount equal to 6 percent of the amount of the excess contributions to such individual's accounts or annuities (determined as of the close of the taxable year). The amount of such tax for any taxable year shall not exceed 6 percent of the value of the account or annuity (determined as of the close of the taxable year).”— 26 U.S.C. §4973(a) (read full statute)

The phrase “determined as of the close of the taxable year” is the statutory anchor — and it's the phrase to use in any legal copy. The 6% is capped at 6% of the account's year-end value, which provides relief in extreme loss years.

What changes after each deadline — practical view

  • Before April 15: withdraw excess + NIA. NIA taxable in contribution year (or year received for HSA). No 6% excise.
  • April 16 – October 15 (with timely filing or 4868):same procedure as above; file an amended return per Pub 590-A's “Filed pursuant to section 301.9100-2” instruction if the original return is already filed.
  • April 16 – October 15 (no timely filing, no 4868): NIA-based correction window has effectively closed. Treat as after-deadline.
  • After October 15: NIA-based correction no longer available. Withdraw principal only (no earnings); 6% excise per IRC §4973 for each year the excess remained "determined as of the close of the taxable year." File Form 5329 for each affected year.

Form 5498 and discovery timing

Form 5498 (IRA contribution information) is issued by your custodian by May 31 — i.e., after April 15. If the 5498 is the document that surfaces the excess, you may already be past the timely window before you knew. The October 15 extension exists in part to accommodate this — but only if you timely-filed your return.

A practical recommendation

If there is any chance you contributed excess, file Form 4868 by April 15 even if you intend to file your actual return earlier. Form 4868 is free, requires only an estimate of your tax liability, and preserves the §301.9100-2(b) extension at zero cost.

Also relevant

Informational, not tax advice. Consult a CPA or Enrolled Agent before acting on a corrective distribution.