Clean energy tax credits got a lot more complicated in a way that has nothing to do with how clean your project is. The One Big Beautiful Bill Act added a set of national-security restrictions, and they can quietly wipe out a credit a business was counting on. If your project relies on the wrong suppliers or the wrong ownership, the credit can disappear even when everything else qualifies.
These are the prohibited foreign entity rules, and for any business claiming energy credits in 2026 and beyond, they are now part of the diligence. Here is what the rules do, which credits they touch, and the material assistance math that decides eligibility.
The One Big Beautiful Bill Act layered two related restrictions onto several clean energy tax credits. The first looks at who owns or controls the taxpayer and its suppliers. The second looks at where the components and materials in a project come from. Fail either test and the credit can be reduced or lost entirely.
The goal is to keep federal energy incentives from flowing to, or depending on, entities tied to countries the government treats as adversaries. For businesses, the practical effect is that a credit now depends not just on building a qualifying project, but on proving your ownership and your supply chain stay clear of prohibited sources.
The rules reach six clean energy credits: Section 45Q for carbon capture, Section 45U for zero-emission nuclear, Section 45X advanced manufacturing, Section 45Y clean electricity production, Section 45Z clean fuel production, and Section 48E clean electricity investment.
If your business claims any of these, the prohibited foreign entity analysis now applies. That covers a wide swath of energy and manufacturing activity, from utility-scale power projects to component makers, so the reach is broad.
The rules define a "prohibited foreign entity," which breaks into two groups worth understanding.
A "specified foreign entity" is the more clear-cut group. It includes designated terrorist organizations, entities identified under OFAC sanctions, Chinese military companies, and the governments of China, Russia, Iran, and North Korea, along with their subsidiaries.
A "foreign-influenced entity" is broader and catches more ordinary businesses by surprise. An entity can fall here if a specified foreign entity has the power to appoint its leadership, owns 25% or more individually, or 40% or more collectively with others, holds 15% or more of its debt, or exercises "effective control" through contracts. That last category means a licensing or supply agreement, not just direct ownership, can pull a business into the rules. Ownership charts and key contracts both need a look.
The supply-chain piece runs on a formula called the material assistance cost ratio (MACR). It measures how much of a project's cost comes from prohibited foreign entities.
The math is straightforward: take total direct costs (T), subtract the costs attributable to prohibited foreign entities (P), and divide the remainder by the total, ((T minus P) divided by T). The result has to clear a minimum threshold for the credit to survive. For 2026, the thresholds differ by credit type, for example around 40% for qualified facilities under Section 45Y and 55% for energy storage under Section 48E, with component-specific percentages for Section 45X. Those thresholds rise in later years, tightening the screws on foreign-sourced content over time.
In plain terms, a project has to source enough of its cost away from prohibited entities to stay above the line. Miss the ratio and the credit is off the table.
Timing here is specific, so it is worth pinning down. For Sections 45X, 45Y, 48E, and 45Q, the ownership-based restrictions generally take effect for tax years beginning after July 4, 2025, which is January 1, 2026 for calendar-year taxpayers. For Sections 45U and 45Z, the specified foreign entity prohibition starts January 1, 2026, and the broader foreign-influenced entity prohibition begins January 1, 2028.
The material assistance rules apply to projects whose construction begins in 2026 or later. So a project breaking ground this year is squarely in scope, and the beginning-of-construction date becomes a key planning lever.
Because the statute moved faster than the regulations, businesses need something to lean on now. Treasury and the IRS provided guidance in February 2026, and taxpayers may rely on the tables in the related IRS notice along with supplier certifications until Treasury issues updated guidance, which is expected by the end of 2026.
That reliance is important, because it lets a business document its material assistance position today using the safe-harbor tables and certifications from suppliers, rather than waiting for final rules. Good supplier documentation is the backbone of any credit claim under these rules.
The prohibited foreign entity rules turn an energy tax credit into a diligence exercise. A project can be technically perfect and still lose its credit over an ownership stake or a supplier that trips the material assistance ratio. For businesses and the CPA firms advising them, that means mapping ownership, reviewing key contracts, tracking component sourcing, and collecting supplier certifications well before filing.
If your firm or your clients are claiming clean energy credits and need to navigate the prohibited foreign entity and material assistance rules, Madras Accountancy can help document the ownership analysis, run the cost ratio, and organize the supplier certifications so the credit holds up.
1. What are the prohibited foreign entity rules? They are restrictions added by the One Big Beautiful Bill Act that can reduce or eliminate certain clean energy tax credits when a taxpayer or its supply chain is tied to prohibited foreign entities.
2. Which energy tax credits do they affect? Sections 45Q, 45U, 45X, 45Y, 45Z, and 48E, covering carbon capture, nuclear, advanced manufacturing, clean electricity production and investment, and clean fuel.
3. What is a prohibited foreign entity? It is either a specified foreign entity (such as sanctioned entities, Chinese military companies, or the governments of China, Russia, Iran, and North Korea and their subsidiaries) or a foreign-influenced entity based on ownership, debt, appointment power, or effective control.
4. What is the material assistance cost ratio? It measures how much of a project's cost comes from prohibited foreign entities, calculated as total direct costs minus prohibited-entity costs, divided by total costs. The result must clear a threshold that varies by credit.
5. What are the thresholds for 2026? They differ by credit, for example roughly 40% for qualified facilities under Section 45Y and 55% for energy storage under Section 48E, with component-specific percentages for Section 45X. The thresholds increase in later years.
6. When do the rules take effect? For Sections 45X, 45Y, 48E, and 45Q, generally for tax years beginning after July 4, 2025. Material assistance rules apply to projects that begin construction in 2026 or later.
7. Can a supply contract alone trigger the rules? Yes. A foreign-influenced entity can be caught through "effective control," which includes certain contracts, not just direct ownership, so licensing and supply agreements need review.
8. What guidance can businesses rely on now? Treasury and the IRS issued guidance in February 2026, and taxpayers may rely on the related notice's tables and supplier certifications until updated guidance is issued, expected by the end of 2026.
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