Tax Planning
Navigating the New Prohibited Foreign Entity (PFE) Rules: A Tax Planning Guide for Developers Using Energy Tax Credits
Recent guidance under Notice 2026-15 introduces “material assistance” restrictions tied to foreign entities that could disqualify energy tax credits, urging energy project developers to reshape sourcing and component decisions.
By NomadicTax Research Team • 5-8 min read • March 24, 2026
## Overview: What Are the PFE & MACR Rules?
Under the **One, Big, Beautiful Bill Act (OBBBA)** effective July 4, 2025, new rules regarding **Prohibited Foreign Entities (PFEs)** were added to U.S. tax law. They prevent taxpayers from claiming certain energy tax credits (e.g. under sections 45X, 45Y, 48E) if a facility or its inputs have “material assistance” from PFEs. A key metric is the **Material Assistance Cost Ratio (MACR)**—the share of cost associated with inputs linked to PFEs. ([irs.gov](https://www.irs.gov/pub/irs-irbs/irb26-11.pdf?utm_source=openai))
On **February 12, 2026**, Notice 2026-15 issued interim guidance on how to calculate MACR, safe harbors, and reliance rules, determining when credits are disallowed due to PFE involvement. ([kpmg.com](https://kpmg.com/us/en/taxnewsflash/news/2026/02/notice-2026-15-guidance-energy-tax-credits-material-assistance-prohibited-foreign-entities.html?utm_source=openai))
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## Key Details & Effective Dates
- **Credits affected**: Clean Electricity Production (45Y), Investment Credit (48E), Advanced Manufacturing (45X) among others. ([millerchevalier.com](https://www.millerchevalier.com/publication/notice-2026-15-provides-guidance-evaluating-material-assistance-section-45y-45x-and-48e?utm_source=openai))
- **Effective for**: Facilities or energy storage tech beginning construction **after Dec 31, 2025**, and eligible components sold in tax years begun after **July 4, 2025**. ([millerchevalier.com](https://www.millerchevalier.com/publication/notice-2026-15-provides-guidance-evaluating-material-assistance-section-45y-45x-and-48e?utm_source=openai))
- **MACR Thresholds**: Determined by type (facility vs component) and build year—these evolve over time. Eg. for 2026: 40% MACR threshold for qualified facilities, 55% for energy storage tech; rising annually. ([foley.com](https://www.foley.com/p/102mis0/irs-releases-guidance-regarding-material-assistance-rules/?utm_source=openai))
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## Safe Harbors & Reliance
Notice 2026-15 offers **interim safe harbor methods** for calculating MACR, including both direct actual cost tracking and tables estimating cost percentages. If using safe harbors, taxpayers must attach required certification statements and support documentation. ([kpmg.com](https://kpmg.com/us/en/taxnewsflash/news/2026/02/notice-2026-15-guidance-energy-tax-credits-material-assistance-prohibited-foreign-entities.html?utm_source=openai))
Taxpayers may **rely** on the guidance in the notice **until** 60 days after forthcoming proposed regulations concerning safe harbor tables are published. ([kpmg.com](https://kpmg.com/us/en/taxnewsflash/news/2026/02/notice-2026-15-guidance-energy-tax-credits-material-assistance-prohibited-foreign-entities.html?utm_source=openai))
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## Planning Strategies & Potential Pitfalls
- Perform supply-chain due diligence: Identify suppliers, component manufacturers, licensors to quantify PFE exposure early.
- Lean toward U.S.-based or non-PFE sources where possible to minimize MACR risk.
- Document everything: component sourcing, licensing agreements, financing, or IP arrangements—necessary for safe harbor reliance or reclamation of credits.
- When considering entering into new contracts (e.g., IP licensing), compare costs and risks under direct method vs safe harbor tables.
- Monitor for update to proposed tables or final rules—these could tighten or relax guidelines.
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## Sample Calculation
Suppose **Project SolarCo** builds a clean energy facility in 2026: total qualified investment is \$10M. If \$3M in components come from PFEs—MACR is 30%. For a 2026 qualified facility, the threshold is 40%. Since 30% < 40%, SolarCo **fails** MACR test and credit would be disallowed—unless safe harbor methods or alternative sourcing reduce PFE cost below threshold.
Alternatively, using safe harbor tables, perhaps similar facility types show typical PFE‐component % as only 25%—then project qualifies under table safe harbor.
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## Takeaways for Energy Developers
- Projects starting construction **after December 31, 2025** must adhere to these new rules.
- Early planning around MACR and PFE exposure could save large sums in credit loss.
- Seeking professional guidance early, particularly in structuring supply chains, is critical.
- Potential stress on procurement and contract inclusion of PFE disclaimers.
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## Final Thoughts
Notice 2026-15’s PFE/MACR regime marks a major shift in energy tax credit eligibility. Developers with projects either underway or in planning need to treat credit eligibility as part of core project viability—not an afterthought. With the proper tools, documentation, and strategy, credit risk can be mitigated—and in many cases credits preserved.