Bonus Depreciation Is Back at 100% — But Your State May Not Have Gotten the Memo

TL;DR: Federal 100% bonus depreciation is back permanently. But more than half of U.S. states don't recognize it — which means a strategy that saves you six figures federally can quietly create a real state tax bill in the same year. Knowing your state's conformity status before you file isn't optional. It's the difference between a strategy that works and one that surprises you at the worst possible moment.

• Federal 100% bonus depreciation is permanent for property acquired after January 19, 2025.

• States fall into three categories: full conformity, full decoupling, and partial conformity.

• Decoupled states require an addback — meaning you owe state tax on income you already deducted federally.

• California's addback on a $480,000 purchase can generate roughly $51,000 in extra state tax in year one.

• The decoupling trend has more than doubled since 2017 and is still accelerating.

The federal government permanently restored 100% bonus depreciation for property acquired after January 19, 2025. That's welcome news for real estate investors and business owners who've been waiting for clarity. Here's the part I keep having to explain on stages and on my podcast, though: that federal deduction doesn't always travel. A growing number of states have decoupled from the federal bonus depreciation rules, which means they require you to add that big federal deduction right back onto your state return — and depreciate the asset slowly over its normal life instead.

The result is a strategy that saves you six figures federally while quietly creating a state tax bill in the same year. I've seen the look on people's faces when this shows up unexpectedly. I'd rather you understand it before you file than after.

Why Is State Decoupling Accelerating?

In 2017, only 13 states fully decoupled from federal bonus depreciation. Today that number has more than doubled, with several more states considering changes for 2026. The reason isn't complicated — states watched federal bonus depreciation drain billions from their budgets after the 2017 tax law. Their response was to decouple, one by one, protecting their revenue base while Washington kept expanding accelerated depreciation in the opposite direction.

💡 The key insight: federal and state tax policy are moving in opposite directions. Washington keeps expanding accelerated depreciation. State capitals keep rejecting it to protect their revenue. Once you see that pattern, the whole picture comes into focus.

Bottom line: the decoupling trend isn't slowing down — it's the dominant direction of state tax policy right now, and it's worth treating it that way.

Key Point: State decoupling has more than doubled since 2017 because states are systematically protecting revenue that federal bonus depreciation was eroding from their budgets.

Which States Conform to Federal Bonus Depreciation — And Which Don't?

States fall into three categories, and knowing which one applies to you shapes everything — from purchase timing to entity structure.

1. Full Conformity States: The Deduction Works at Both Levels

These states follow the current Internal Revenue Code, so your federal bonus depreciation flows directly through to your state return. According to Thomson Reuters, examples include Colorado, Kansas, and Louisiana. In these states, your cost segregation study or equipment purchase delivers its full benefit at both levels. The math works the way most people assume it works everywhere.

Key Point: Full conformity states let bonus depreciation work exactly as intended — no addback, no surprises, full federal benefit reflected at the state level too.

2. Decoupled States: The Addback Problem

These states have rejected federal bonus depreciation entirely. The decoupled list for 2026 includes California, New York, New Jersey, Pennsylvania, Massachusetts, Connecticut, Maryland, Tennessee (conforms to the TCJA phase-down schedule, not the OBBBA's 100% restoration), North Carolina, Indiana, Wisconsin, and the District of Columbia, among others. In these states, you take the federal deduction — then add it back for state purposes and depreciate over the standard MACRS schedule. You eventually recover the deduction, it just takes years instead of one filing.

Key Point: Decoupled states don't eliminate the deduction — they defer it. The state tax bill arrives in year one while the deduction slowly returns over the asset's useful life.

3. Partial Conformity States: The Trickiest Category

States like Arkansas, Connecticut, and Kentucky allow conformity in some tax years or under certain conditions, and apply different treatment in others. These are the trickiest jurisdictions because the answer changes depending on the year, the asset, and sometimes the entity type.

⚠️ Your tax professional earns their fee in partial conformity states. There's no clean universal answer — it requires a fact-specific analysis every single time.

How Does California's Decoupling Work? A Real Numbers Example

Real numbers make this clearer than abstract rules, so here's a documented scenario from a 2026 analysis.

You place $480,000 of qualifying property in service. Federally, you deduct the full amount — at a 37% marginal rate, that saves you roughly $178,000 in federal tax. California requires the full $480,000 addback. The state only allows you the first-year MACRS amount — roughly $96,000 on a 5-year asset. That leaves a $384,000 addback at California's top 13.3% rate — about $51,000 in extra state tax in year one.

The same purchase that saved you $178,000 federally created a $51,000 state bill in the same year. If you didn't plan for that, your cash flow projections just got a painful surprise.

Key Point: California's decoupling doesn't just reduce your federal benefit — it front-loads a state tax liability in the same year the federal deduction lands, creating a cash flow gap that most investors don't see coming.

What Happens in New York When a Loss Creates a Tax Bill?

New York deserves its own section because what happens there is one of the most counterintuitive outcomes in state tax law. Consider a documented scenario from EisnerAmper: a non-resident of New York has $1 million of passive income from Florida sources and a $1 million passive loss from New York sources — both generated by bonus depreciation. Federally, that nets to zero income.

For New York purposes, the $1 million loss gets disallowed, and an $800,000 addback related to bonus depreciation gets required. That taxpayer pays New York income tax on $800,000 of income — in a year when their only New York activity produced a million-dollar loss. A loss became a tax bill. This is exactly the kind of trap that hides inside a strategy everyone assumes is free money.

Key Point: New York's decoupling creates a scenario where passive losses and bonus depreciation addbacks can combine to produce taxable income in a year with zero net economic gain — a result that defies most investors' intuitions entirely.

What Does State Conformity Mean for Cost Segregation Studies?

I've spent decades helping investors and business owners implement cost segregation studies, so I want to be direct about how state conformity interacts with them. A cost segregation study reclassifies building components into shorter-life property, which unlocks bonus depreciation on a large share of your purchase price. In a conforming state, that benefit works at both the federal and state level — the study delivers exactly what it promises.

In a decoupled state, the relationship flips on the state side. The larger the federal deduction the study generates, the larger the state addback becomes. The study still delivers enormous federal value, and the state deduction still arrives over time — you simply need to model both sides before you commit. A good study provider will show you both numbers without prompting.

Education precedes transaction. If you don't understand what a strategy does in your specific state, it's not ready to execute — and anyone selling it to you should welcome that conversation, not sidestep it.

Key Point: Cost segregation studies remain one of the most effective federal tax tools available — but in decoupled states, the state-side math changes the cash flow picture in year one, and every serious study should model that upfront.

Does Purchase Timing Change in Decoupled States?

Conventional wisdom says accelerate purchases at year-end to capture the deduction. In a conforming state, that logic holds. In a decoupled state, the calculus shifts. A December purchase gives you the federal benefit immediately and the state benefit slowly over the asset's life — while triggering the state addback right away. If cash is tight, a purchase planned for early the following year defers the federal and state effects together, keeping them aligned and avoiding a first-year cash flow squeeze.

In heavily decoupled states, the year-end rush can work against you. That's the kind of detail a five-minute conversation about your state's rules surfaces — and it's why tax strategy deserves the same attention as the investment itself.

Key Point: Purchase timing isn't just a federal planning variable — in decoupled states, the timing of when you place assets in service directly affects the year your state addback hits, and that's worth modeling before you sign anything.

Key Takeaways

• Federal 100% bonus depreciation is permanent for property acquired after January 19, 2025 — one of the most significant wealth-building tools available to investors and business owners right now.

• States fall into three categories: full conformity (Colorado, Kansas, Louisiana), full decoupling (California, New York, New Jersey, Pennsylvania, Massachusetts, and others), and partial conformity (Arkansas, Connecticut, Kentucky).

• Decoupled states require an addback, which creates a real state tax bill in the same year your federal bill drops. California's version costs roughly $51,000 on a $480,000 purchase.

• The decoupling trend has more than doubled since 2017 and shows no signs of reversing — it's the dominant direction of state tax policy.

• Purchase timing, cost segregation modeling, and multi-state planning all change based on your conformity status — and those variables are worth analyzing before the transaction, not after.

• New York's treatment is uniquely aggressive: bonus depreciation addbacks can produce taxable income in a year when your only New York activity generated a loss.

• A good cost segregation study provider will show you the federal and state numbers side by side — if they don't offer that, ask for it.

None of this diminishes the strategy. It means the strategy deserves a complete picture before you execute — and once you see both the federal and state sides clearly, you'll make sharper decisions than most of the market. That clarity is the whole point.

Frequently Asked Questions

Is 100% bonus depreciation permanent now?
Yes. For property acquired after January 19, 2025, the federal government permanently restored 100% bonus depreciation. It no longer phases down the way it did from 2018 through 2026 under prior law.

What does it mean when a state "decouples" from federal bonus depreciation?
It means the state doesn't recognize the federal accelerated deduction. You claim the full deduction on your federal return, then add it back on your state return and depreciate the asset over its standard useful life instead — which spreads the state deduction across many years rather than one.

Which states have decoupled from bonus depreciation in 2026?
The decoupled list includes California, New York, New Jersey, Pennsylvania, Massachusetts, Connecticut, Maryland, Tennessee (which conforms to the TCJA's phase-down schedule rather than the OBBBA's 100% restoration — so Tennessee allows only 40% bonus for 2025 assets, not 100%), North Carolina, Indiana, Wisconsin, and the District of Columbia, among others. The list has more than doubled since 2017.

Do partial conformity states allow any bonus depreciation?
Yes, but selectively. States like Arkansas, Connecticut, and Kentucky allow conformity in certain tax years or for certain asset types, and then apply different rules in others. These states require a fact-specific analysis — the answer changes based on the year, the asset, and sometimes the entity type.

How does California's bonus depreciation addback work?
California requires you to add back the full federal bonus depreciation deduction and allows only the standard first-year MACRS amount instead. On a $480,000 purchase, that generates roughly a $384,000 addback — which at California's 13.3% top rate means approximately $51,000 in additional state tax in year one.

Can a bonus depreciation deduction create taxable income in New York?
It can, and it has. EisnerAmper documented a scenario where a non-resident with $1 million of passive income from Florida and a $1 million passive loss from New York ended up owing New York income tax on $800,000 of income — because the New York loss was disallowed and an $800,000 addback was required. Federally, the net was zero.

Should I still pursue a cost segregation study in a decoupled state?
The federal value of a cost segregation study remains significant regardless of your state's conformity status. The key is modeling both sides before you commit — the federal benefit arrives in year one, and the state benefit arrives gradually. A well-run study will show you both numbers clearly so you can plan your cash flow accordingly.

Does year-end purchase timing still make sense in decoupled states?
Not always. In a decoupled state, a December purchase triggers the federal benefit immediately and the state addback immediately — while the state deduction spreads across years. If cash is tight, an early-year purchase in the following tax year aligns the federal and state effects together, which can make the cash flow picture easier to manage.