Jessica I. Marschall, CPA November 8th, 2025
A New Phase for the Corporate AMT
In mid-2025, the U.S. Treasury and IRS issued a series of changes that significantly ease compliance with the Corporate Alternative Minimum Tax (CAMT)—a 15% minimum tax on adjusted financial statement income (AFSI) for large corporations. These updates aim to simplify how companies determine whether they are subject to the CAMT and how they calculate it, especially in complex ownership and partnership structures.
The most impactful change is an optional “interim simplified method” that gives corporations a faster and clearer way to determine if they fall under the CAMT. Treasury released several interim guidance packages throughout 2025, addressing partnerships, consolidated groups, and companies emerging from financial distress.
Key Highlights from the 2025 Guidance
1. Interim Simplified Method for Determining Applicability
Under IRS Notice 2025-27 (issued June 2, 2025), corporations can now use an optional simplified approach to determine if they are “applicable corporations” for CAMT purposes, with thresholds of $800 million for U.S.-parented groups and $80 million for foreign-parented groups Internal Revenue Service Cherry Bekaert, rather than the statutory $1 billion and $100 million levels.
This method can be applied to any taxable year for which the original federal return has not yet been filed as of June 23, 2025 Internal Revenue Service.
The IRS also provided penalty relief for underpayment of CAMT-related estimated taxes for tax years beginning after December 31, 2024, and before January 1, 2026 Cherry Bekaert.
For many companies, this optional method offers a practical way to conclude they are not subject to CAMT—without undertaking the full statutory analysis.
2. Simplified Partnership Computations
IRS Notice 2025-28 (issued July 29, 2025) introduces two new ways for corporate partners to calculate their share of partnership-related AFSI: a “top-down” method based on consolidated financials and a “taxable-income” method that can be used in limited circumstances CBIZ.
These changes substantially reduce the need for complex data transfers from partnerships and ease administrative burdens for corporations with multiple pass-through interests.
3. Interim Clarifications for Complex Situations
Additional interim notices—2025-46 and 2025-49 (both released September 30, 2025)—addressed several technical areas including the treatment of corporate transactions and restructuring events, the impact of debt discharge and bankruptcy-related adjustments on AFSI, and consolidated group rules and the use of financial statement net operating losses (FSNOLs) PwC.
Together, these measures provide temporary but much-needed guidance for corporations navigating major transactions or reorganizations.
4. Political and Policy Scrutiny
A September 9, 2025 letter from Senator Elizabeth Warren and other lawmakers criticized Treasury’s approach, warning that some simplifications could create avoidance opportunities for large corporations U.S. Senator Elizabeth Warren. The letter specifically noted that Notice 2025-27’s $800 million threshold was significantly higher than the Biden Administration’s threshold of $500 million, with no explanation provided for the change U.S. Senator Elizabeth Warren. The letter signals that future regulatory revisions may tighten the rules again once proposed regulations are finalized.
What This Means for Corporate Tax Planning
- Evaluate Eligibility Early: Companies below the $800M (or $80M) AFSI threshold may rely on the simplified method, but they should carefully document their determination.
- Model Partnership Impacts: The top-down and taxable-income methods can affect AFSI timing and consolidated reporting—early modeling is recommended.
- Leverage Penalty Relief: The 2025 transition year includes penalty relief for estimated CAMT underpayments through tax years beginning before January 1, 2026; this provides short-term cash flow flexibility.
- Prepare for Further Change: Treasury’s mention of additional interim guidance and reproposed CAMT regulations likely indicates that final CAMT regulations are unlikely in the near or medium term KPMG. Permanent regulations may reintroduce complexity—especially if congressional scrutiny continues.
Bottom Line
The Treasury’s 2025 guidance on the Corporate AMT offers meaningful short-term relief and clarity for large corporations, but the long-term framework is still evolving. Companies should use this period to solidify their data collection and documentation processes while monitoring for new proposed regulations expected later in 2025 or 2026.
For strategic guidance on how these changes affect your tax planning, reach out to our advisory team at MAS LLC.
Sources
- U.S. Department of the Treasury & IRS: “New Simplified Method for Determining Status for Corporate Alternative Minimum Tax” (IRS.gov, June 2, 2025)
- IRS Notices 2025-27 (June 2, 2025), 2025-28 (July 29, 2025), 2025-46 and 2025-49 (September 30, 2025)
- Grant Thornton LLP: “IRS guidance adjusts application of corporate AMT” (September 2025)
- Ernst & Young LLP: “Corporate Alternative Minimum Tax: New Guidance” (Referenced in original but not verified)
- Sen. Elizabeth Warren et al.: Letter to Treasury Secretary Scott Bessent re: CAMT Guidance (September 9, 2025)
- PwC: “IRS notice on CAMT compliance and estimated tax penalty relief” (June 2025)
- KPMG: “Notice 2025-27 provides additional CAMT interim guidance” (June 2, 2025)
- Sullivan & Cromwell LLP: “IRS Issues Interim Guidance on Corporate Alternative Minimum Tax” (September 30, 2025)
- BDO: “IRS Sets Out Modifications to CAMT Proposed Rules in Interim Guidance” (October 2025)
