Interim Guidance — 2025 Inst 4626 (PDF)

Proposed Regulations—Proposed Applicability Dates and Reliance Prior to Applicability The Treasury Department and the IRS issued a Notice of Proposed Rulemaking published in the Federal Register on September 13, 2024. See 89 FR 75062, as corrected by 89 FR 104909. Until finalized, these proposed regulations are non-binding and subject to change. Some sections of the proposed regulations are proposed to apply to tax years ending after September 13, 2024 (“specified proposed regulations”). When final regulations are published in the Federal Register, these sections would apply to tax years ending after September 13, 2024. Other sections of the proposed regulations are proposed to apply to tax years ending after the date that final regulations are published in the Federal Register (“other proposed regulations”). Corporations would not be required to apply these sections of the proposed regulations until final regulations are published in the Federal Register. Special rules, discussed below, are

Instructions for Form 4626 (2025) Catalog Number 64443L Jan 29, 2026 Department of the Treasury Internal Revenue Service www.irs.gov

provided for corporations that choose to rely on sections of the proposed regulations for tax years ending on or before their proposed applicability dates.

Specified Proposed Regulations—Proposed Applicability Date The following sections of the proposed regulations apply to tax years ending after, and, in certain cases, transfers (as defined in Proposed Regulations section 1.56A-4(b) (3)) occurring after, September 13, 2024.

Proposed Regulations sections 1.56A-1 through 1.56A-4.
Proposed Regulations sections 1.56A-6 through 1.56A-11.
Proposed Regulations section 1.56A-13.
Proposed Regulations section 1.56A-14.
Proposed Regulations section 1.56A-17.
Proposed Regulations section 1.56A-26.
Proposed Regulations section 1.56A-27.
Proposed Regulations sections 1.59-2 through 1.59-4.

The provisions of Proposed Regulations section 1.56A-5(l)(2)(ii) and (iii) apply to tax years ending after September 13, 2024, and on or before the date of publication of final regulations in the Federal Register, in order to coordinate certain provisions of the specified proposed regulations.

Reliance on Specified Proposed Regulations for Tax Years Ending Before Proposed Applicability Date Corporations may rely on the specified proposed regulations for any tax year ending on or before September 13, 2024, provided the corporation, and each member of its test group determined under Proposed Regulations section 1.59-2 for that tax year, consistently follows all of the specified proposed regulations in their entirety in that tax year and each subsequent tax year (taking into account any changes to its test group determined under Proposed Regulations section 1.59-2 for each subsequent tax year) until the first tax year in which the final regulations are applicable and also applies the rules described in Proposed Regulations sections 1.56A-4 and 1.56A-6 that apply to transfers (as defined in Proposed Regulations section 1.56A-4(b)(3)) to any transfers occurring in such years.

A corporation may rely on the rules described in Proposed Regulations sections 1.56A-4 and 1.56A-6 that apply to transfers for a transfer occurring on or before September 13, 2024, provided the corporation, and each member of its test group determined under Proposed Regulations section 1.59-2 for the tax year of the corporation that includes the date of the transfer, consistently follow all of the rules in Proposed Regulations sections 1.56A-4 and 1.56A-6 for all such transfers occurring on or before September 13, 2024, during a tax year of the taxpayer and each subsequent tax year until the final regulations are applicable to such transfers, and if any such transfers occur in tax years ending on or before September 13, 2024, must rely on the specified proposed regulations for such tax years.

Other Proposed Regulations—Proposed Applicability Dates The following sections of the proposed regulations apply to tax years ending after the date the final regulations are published in the Federal Register:

Notice 2025-27, 2025-26 I.R.B. 1615, available at IRS.gov/irb/2025-26_IRB#NOT-2025-27 .

• Notice 2025-28, 2025-34 I.R.B. 316, available at IRS.gov/irb/2025-34_IRB#NOT-2025-28 .

Proposed Regulations section 1.56A-5 (other than section 1.56A-5(l)(2)(ii) and (iii)).
Proposed Regulations section 1.56A-12.
Proposed Regulations section 1.56A-15.
Proposed Regulations section 1.56A-16.
Proposed Regulations sections 1.56A-18 through 1.56A-25.

The provisions of the following sections apply to consolidated return years for which the due date of the income tax return (without extensions) is after the date of publication of final regulations in the Federal Register:

Proposed Regulations section 1.1502-2.
Proposed Regulations section 1.1502-53.
Proposed Regulations section 1.1502-56A.

Reliance on Other Proposed Regulations for Tax Years Ending Before Proposed Applicability Date Corporations may rely on one or more of the other proposed regulations for any tax year ending on or before the date the final regulations are published in the Federal Register provided that, for each section on which the corporation relies, the corporation, and each member of its test group determined under Proposed Regulations section 1.59-2 for that tax year, consistently follow that section in its entirety and also follow all of the specified proposed regulations in their entirety in that tax year and each subsequent tax year (taking into account any changes to its test group determined under Proposed Regulations section 1.59-2) until the first tax year in which the final regulations are applicable and also applies the rules described in Proposed Regulations sections 1.56A-4 and 1.56A-6 that apply to transfers (as defined in Proposed Regulations section 1.56A-4(b)(3)) to any transfers occurring in such years. Notwithstanding the prior sentence, a corporation may not rely on Proposed Regulations sections 1.56A-18, 1.56A-19, and 1.56A-21 in any tax year unless the corporation and each member of its test group determined under Proposed Regulations section 1.59-2 for that tax year rely on each of those sections in its entirety. In addition, Notice 2025-28 provides that a taxpayer may rely on Proposed Regulations section 1.56A-5 (excluding Proposed Regulations sections 1.56A-5(l)(2)(ii) and (iii)) if the taxpayer and each member of its test group determined under Proposed Regulations section 1.59-2 consistently follow that section in its entirety, regardless of whether the taxpayer also relies on Proposed Regulations section 1.56A-20, and vice versa.

Reliance on Interim Notice Guidance The Treasury Department and the IRS also issued interim guidance published in the Internal Revenue Bulletin.

2 Instructions for Form 4626 (2025)

Notice 2025-46, 2025-43 I.R.B. 533, available at IRS.gov/irb/2025-43_IRB#NOT-2025-46 .

• Notice 2025-49, 2025-44 I.R.B. 627, available at IRS.gov/irb/2025-44_IRB#NOT-2025-49 .

Taxpayers may be able to rely on some or all of the interim guidance provided, subject to the following applicability dates and reliance conditions for each of the notices:

A corporation may use the interim simplified method provided in Notice 2025-27 for determining applicable corporation status for any tax year ending on or before the date that a Treasury Decision adopting a simplified method pursuant to section 59(k)(3)(A) is published in the Federal Register and for which the original federal income tax return has not been filed as of June 23, 2025.