The Corporate Alternative Minimum Tax (CAMT): Who the 15% Book-Income Tax Actually Hits
Part of our 2025 Tax Law Changes guide — the complete breakdown of the One Big Beautiful Bill Act.
You may have seen headlines about a new 15% corporate minimum tax. It’s real — but it’s narrow. Here’s who the Corporate Alternative Minimum Tax (CAMT) actually affects, and, just as importantly, who it doesn’t.
What CAMT is
The CAMT imposes a 15% minimum tax on the adjusted financial statement income (AFSI) — essentially book income with adjustments — of the very largest corporations. It was designed so highly profitable companies can’t use deductions and credits to drive their effective tax rate far below 15%.
Who it applies to
- Generally, “applicable corporations” with average annual AFSI over $1 billion (measured over a three-year period).
- It does not apply to S corporations, REITs, RICs, or the vast majority of businesses.
Why smaller firms still care
- If you serve large corporate clients or their subsidiaries, book-to-tax modeling now carries a new layer.
- Financial-statement income takes on added tax significance — coordination between the tax and reporting teams matters.
- For everyone else, it’s useful context when clients ask, “Does that 15% minimum tax apply to me?” (Almost always: no.)
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This article is general information for tax and accounting professionals and is not tax, legal, or accounting advice. Rules, rates, and thresholds change and have specific effective dates — confirm current requirements with the IRS, U.S. Customs and Border Protection, or qualified counsel before acting or advising clients.
