Can You Explain The Extended IRS AMT Underpayment Waiver?

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In a recent development, the IRS has issued Notice 2024-47, extending the IRS AMT underpayment waiver of the addition to tax under Section 6655 for corporate taxpayers’ failure to pay estimated income tax specifically tied to their Section 55 corporate alternative minimum tax (AMT) liabilities. This extension is a continuation of the relief initially provided in Notice 2024-33 and is crucial for corporations navigating the complexities of the revised corporate AMT under the Inflation Reduction Act of 2022.

Background of the IRS AMT underpayment waiver

Initially, the relief under Notice 2024-33 covered the installment of estimated tax due on April 15, 2024, or May 15, 2024, for tax years beginning in 2024. This initial waiver was designed to mitigate challenges corporations faced with the newly adjusted corporate AMT calculations. Recognizing ongoing difficulties, the IRS has now extended the IRS AMT underpayment waiver and penalty relief to include any installment of estimated tax due on or before August 15, 2024.

Scope of the Extended Waiver

The extended waiver applies specifically to underpayments of estimated taxes that are attributable to the corporate AMT for the 2024 tax year. It does not cover underpayments related to other tax provisions outside of Section 55(a). For any installments due after August 15, 2024, standard penalties will apply, making it crucial for corporations to adjust their tax strategies accordingly.

Reasons Behind the Waiver Extension

The IRS cites “challenges associated with determining whether a corporation is an Applicable Corporation and the amount of corporate AMT liability” as key reasons for extending this relief. This decision also aligns with the IRS’s goal of sound tax administration, acknowledging that many corporations are still adapting to the significant tax reform enacted by the Inflation Reduction Act.

Impact of the Corporate AMT

Under the Inflation Reduction Act, a new 15% minimum tax based on book income now applies to corporations with adjusted financial statement income over $1 billion. This substantial change aims to ensure that highly profitable corporations pay a minimum level of tax. The complexity of calculating this tax based on book income has led to practical difficulties for affected corporations, prompting the need for continued relief from estimated tax penalties.

What Corporations Need to Do

Corporations must take several steps in response to this extension:

  1. Review Tax Calculations: Corporations should carefully review their calculations of the corporate AMT to understand the extent of potential underpayments.
  2. Plan for Future Installments: With the waiver not extending beyond August 15, 2024, corporations need to plan their subsequent estimated tax payments to avoid penalties.
  3. Document Compliance Efforts: Maintaining detailed documentation of efforts to comply with the corporate AMT calculations and the related tax payments will be crucial, especially if audited.
  4. Consult Tax Professionals: Given the complexities of the corporate AMT and the implications of the waiver, consulting with tax professionals is advisable to ensure full compliance and optimal tax planning.


The IRS’s extension of the penalty relief for underpayment of estimated taxes due to the corporate AMT is a welcome development for affected corporations. It provides additional time to adjust to the new tax regime while mitigating the financial impact of potential compliance errors during this transition period.

Meta Description: Learn about the IRS’s extension of the waiver for penalties on underpaid estimated corporate AMT, crucial for tax planning and compliance for corporations in 2024.

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What is the New IRS Waiver for Underpayment of Estimated Taxes?

The IRS issued Notice 2024-33, easing underpayment penalties for corporations’ CAMT liabilities, aiding tax planning post-Inflation Reduction Act, with detailed compliance steps required.

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