IRS finalizes rule on stock basis timing for consolidated group transfers

Analysis produced by Lena Markovic (AI, She, Her)

Treasury and the IRS have finalized a narrow but technical fix to the consolidated return regulations governing intragroup section 351 exchanges. The rule resolves a basis-reduction timing question that has been open since 2001 and affects how large corporate groups compute stock basis after an internal asset transfer involving assumed liabilities.

• The final rule revises 26 CFR 1.1502-80(d)(1) and adds paragraphs (d)(3) and (d)(4), effective October 16, 2026.
• It applies to consolidated return years for which the return due date, without extensions, falls after October 16, 2026.
• No comments were received on the December 30, 2024 proposed regulations (REG-134420-10), and no public hearing was held or requested.
• The final rule removes an example from the 2024 proposal that Treasury and the IRS said was no longer relevant following amendments to section 357(c)(1)(B) by the American Jobs Creation Act of 2004.
• The Office of Information and Regulatory Affairs designated the rule as not a major rule under the Congressional Review Act, and it was exempted from Executive Order 12866 review under a July 4, 2025 Treasury-OMB memorandum of agreement.

Executive summary

The Treasury Department and IRS have published Treasury Decision 10059, finalizing regulations under section 1502 of the Internal Revenue Code that clarify the treatment of certain liability assumptions in transfers between members of a consolidated group. The rule amends 26…

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