State Adoption of OBBBA Tax Changes: What to Expect, Where the Friction Will Be, and How to Plan Without Guesswork
Todd Phillips
Jan 23
11 min read
The federal government can amend the Internal Revenue Code with a single vote cycle. States cannot. Even when a state “conforms” to federal law, that conformity is mediated through state-specific rules, budget pressures, administrative capacity, and—most importantly—legislative calendars.
That mismatch is the practical problem created by the One Big Beautiful Bill Act (OBBBA). The OBBBA made sweeping federal changes, including extending and amending provisions affecting businesses, individuals, and families that were otherwise scheduled to expire at the end of 2025. State taxpayers and practitioners are now in the familiar but uncomfortable position of knowing what federal law says while not knowing—at least not uniformly—what states will do with it.
This post explains what the early data shows about state responses, why the states are unlikely to move together, and the practical steps taxpayers should take now to control compliance risk and avoid preventable surprises. We recap a survey
completed by Bloomberg Tax, available by download here.
1. The threshold point: “Federal changed” does not mean “state changed”
Many state income tax systems use the federal tax base as a starting point (federal taxable income, federal AGI, etc.). That starting point is not a guarantee of adoption. It is a reference point. States retain the ability to:
update conformity automatically or only by legislation,
conform to some federal changes but not others,
conform but impose addbacks or alternative state computations,
conform on a delayed basis (or only prospectively),
or temporarily decouple while analyzing fiscal impact.
OBBBA will exacerbate these differences because it is broad and, in many cases, may reduce the tax base that flows into state calculations—creating immediate budget tension in states that rely heavily on income tax revenue.
2. What the Bloomberg Tax survey reveals about how states are approaching OBBBA
Bloomberg Tax’s State Response to 2025 Federal Tax Changes Survey provides a useful snapshot of the state posture. The questionnaire was sent to every state, the District of Columbia, and New York City (52 jurisdictions). Forty-one responded. The jurisdictions that declined to participate are listed in the executive summary.
The survey focused on three operational questions:
Has the state studied (or will it study) the revenue impact of OBBBA?
Is the legislature likely to address conformity in the next session?
Will the revenue department issue guidance—and if so, will it come all at once or in pieces?
That framework matters because it aligns with the three stages taxpayers experience after major federal change: (i) uncertainty, (ii) transitional compliance, and (iii) stabilized filing positions (often still nonuniform across states).
A. Compliance complexity is the baseline, not the exception
The survey summary states directly that taxpayers must decide how to proceed during the period where federal law is enacted but state law has not been updated, and then must perform the “arduous task” of identifying and complying with the resulting changes once states act.
From the multistate business perspective, the concern is not theoretical. As Fred Nicely (Council on State Taxation) put it, “Their biggest concern is how are they going to comply with all the states’ laws …”
That concern is well-founded. OBBBA is not one change. It is a set of changes that can alter taxable income, timing, and attribute utilization. The result is that taxpayers may need to maintain multiple computational tracks (federal and state, and state-by-state within the state group) until legislatures and departments of revenue settle on final positions.
B. Budget constraints are a decisive driver
The survey makes a point that experienced practitioners will recognize: conformity decisions are rarely pure “policy alignment” questions. They are revenue questions.
The executive summary describes expected revenue pressure from two directions:
reductions to the portion of the federal tax base that states use as a starting point, and
potential reductions in federal grant funding, which can amplify state budget stress.
This matters because budget stress tends to produce predictable state behaviors: selective decoupling from expensive federal provisions, delayed adoption, or conformity coupled with offsetting base-broadening adjustments.
C. Revenue analysis is happening, but it is not uniform—and it can be prerequisite to “knowing what the law is”
The survey reports that 22 states had already completed analysis of OBBBA’s revenue impact, and three more planned to do so. It also notes that some states rely on existing summaries or related tools rather than running a full independent study.
Critically, the report highlights that some states cannot even quantify impact until they determine which provisions automatically flowed into their codes under existing conformity rules. In other words, in certain jurisdictions, the first step is clarifying whether OBBBA already changed state law by operation of the state’s conformity mechanism.
This is the practical explanation for why guidance can lag: agencies are not merely interpreting new rules; in some cases they are determining what their current law already does.
D. Legislatures are moving more slowly than many expected
The executive summary notes that, since OBBBA’s enactment on July 4, only a limited number of jurisdictions had passed legislation addressing adoption of the federal changes, listing Delaware, the District of Columbia, Illinois, Michigan, and Pennsylvania.
It then reports the survey’s results on anticipated legislative activity in the next session. The chart on page 3 (titled States Split on Forthcoming Conformity Legislation) illustrates the distribution among responding jurisdictions:
16 anticipate addressing conformity legislation,
8 responded “depends,”
7 responded “no,” and
10 did not respond to that question.
The “depends” category should be read for what it is: an explicit statement that timing and outcomes are uncertain, commonly because fiscal notes are incomplete, leadership has not prioritized the issue, or the legislature intends to wait for political and revenue clarity.
E. Guidance from departments of revenue is expected—but it will be staggered and uneven
The executive summary emphasizes that guidance will not arrive in a clean, coordinated package. Marilyn Wethekam (COST) summarized the taxpayer experience succinctly: “it’s going to be a very difficult year because you don’t have a lot of guidance out there …”
The survey’s results support that point. On whether departments anticipate issuing guidance, the chart on page 4 (titled Most States to Issue Guidance Next Year) shows:
21 responded “yes,”
8 responded “depends,”
7 responded “no,” and
5 did not respond.
Among the states planning to issue guidance, the executive summary notes that 12 expect to issue it all at once, while 7 expect guidance to be released in separate parts.
From a planning standpoint, this is the key operational takeaway: guidance may arrive piecemeal, with differing effective dates, and it may be contingent on whether legislative changes are enacted.
3. Conformity is not one decision; it is a layered framework
Taxpayers often discuss “conformity” as if it were binary. For OBBBA planning, it is better to treat conformity as a three-layer framework.
Layer 1: The state’s general conformity posture
Most states fall into general categories such as:
rolling conformity (federal changes flow through automatically, subject to state modifications),
fixed-date (static) conformity (state conforms to the IRC as of a specific date), or
selective conformity (state adopts or rejects specific federal provisions).
The executive summary notes that the broader Bloomberg Tax report includes a chart of state conformity rules, underscoring that the baseline posture differs materially across jurisdictions.
Layer 2: Automatic decoupling mechanisms for “significant” federal changes
Even rolling-conformity states may have statutory or procedural mechanisms that effectively pause adoption of major federal changes until the legislature acts.
The executive summary describes that some states automatically decouple from new federal legislation that has significant state tax effect to give the legislature time to decide whether to conform or decouple. Maryland and Virginia are highlighted in this context.
For taxpayers, this is a common source of surprises: “rolling conformity” can be directionally helpful, but it is not a substitute for provision-by-provision analysis when the state has an automatic decoupling trigger.
Layer 3: Provision-by-provision adoption, modification, or decoupling
This is where budget analysis becomes determinative. Clark Calhoun’s description of the legislative workflow is direct: “The first step is generally to review the budget impact of conformity to each provision.”
That reality explains why two states with similar general conformity rules can reach different outcomes on a specific OBBBA provision—particularly when the provision has meaningful near-term revenue cost.
4. OBBBA provisions most likely to fracture across states
Bloomberg Tax asked states about whether they have issued or plan to issue guidance on provisions that are “top of mind” for taxpayers and practitioners, including changes that:
limit the interest expense deduction (IRC §163(j)),
permanently expand bonus depreciation (IRC §168(k)),
accelerate deductions for research and experimental expenditures / increased asset expensing (IRC §174A), and
replace the GILTI calculation with NCTI (IRC §951A).
The survey reports that 61% of responding states plan to address—or have addressed—conformity with at least one of the provisions asked about. However, it also notes that each individual provision question received responses from less than half the states, leaving meaningful “gaps in guidance.”
From a practical perspective, these provisions share one feature: they affect taxable income in ways that materially impact both cash taxes and reporting, and they often create timing differences that can require parallel federal/state computations.
5. The compliance risk that matters most: timing mismatches
For many taxpayers, the most consequential issue will not be whether a state ultimately conforms. It will be:
whether conformity (or decoupling) applies retroactively or prospectively,
whether it applies to the same tax year as federal changes,
whether interim forms or administrative positions differ from later-enacted statutes, and
whether the state imposes unique addbacks, caps, or modifications.
The executive summary explicitly anticipates complexity driven by differing approaches, effective dates, and staggered guidance.
The result is a real possibility that, for a transitional period, taxpayers will be required to file:
in one jurisdiction as if the OBBBA change is fully in effect,
in another as if it does not exist (yet),
and in a third with partial adoption that requires separate state-only computations.
This is not merely a compliance inconvenience. It affects estimated tax payments, financial reporting positions (where applicable), transactional pricing, and the ability to forecast cash flows.
6. Practical implications by taxpayer profile
Below are three common profiles where OBBBA conformity divergence is likely to be most disruptive. These are not the only profiles; they are the ones where taxpayers most frequently encounter state computational fragmentation.
Profile A: Multistate operating businesses with leverage (IRC §163(j) risk)
For leveraged operating businesses, §163(j) changes can shift interest expense deductibility. If states diverge on conformity, taxpayers may face:
state-by-state interest limitation computations,
misalignment between federal and state interest carryforwards,
increased complexity in combined reporting environments, and
volatility in estimated payments and quarterly provision calculations.
Because the executive summary identifies §163(j) as among the provisions most states are likely to address in guidance, taxpayers should expect state-level positions to evolve during the transition period.
Planning implication: treat interest limitation as a multistate data problem (inputs, entity-level sourcing, carryforward tracking), not merely a software output.
Profile B: Real estate and asset-intensive businesses (IRC §168(k) risk)
Bonus depreciation and related cost recovery rules are among the most frequent state decoupling points, even outside OBBBA. If OBBBA expands bonus depreciation and states respond unevenly, taxpayers may need to maintain:
separate federal and state depreciation schedules,
state-specific addback computations,
different basis tracking for dispositions, and
different NOL trajectories by state.
The risk is compounding: depreciation schedules are cumulative. Inconsistent tracking in year one becomes permanent friction in year three.
Planning implication: prioritize asset-level data hygiene now, especially for placed-in-service dates, class lives, component allocations, and disposition reporting.
Profile C: Businesses with material R&D and software development expenditures (IRC §174A risk)
Where federal rules change capitalization or accelerate deductions for research and experimental expenditures, state conformity can become an immediate revenue issue for states and a planning issue for taxpayers.
The executive summary notes that §174A is among the provisions most states said were likely to receive guidance.
Planning implication: model the cash tax impact under (i) full conformity, (ii) decoupling, and (iii) partial conformity by key state. Do not assume uniform adoption.
7. Why a “wait-and-see” posture is not operationally viable
Taxpayers can wait for guidance, but business activity does not pause. During the transition period, taxpayers still must:
make estimated payments,
close financials,
allocate transaction consideration,
price deals,
structure entity flows, and
plan cash needs.
The survey summary quotes Jamie Yesnowitz emphasizing the forecasting challenge: the lack of clarity makes it difficult to identify where significant state liability changes will occur and to estimate aggregate corporate income taxes, and he describes estimating as “extremely challenging.”
In other words, waiting may reduce the risk of being “wrong” on a technical position, but it increases the risk of being operationally unprepared (misestimated payments, incomplete data capture, and delayed compliance readiness).
8. A planning framework that works in the real world: build a living state conformity model
The executive summary’s recommendation is straightforward: taxpayers can minimize impact through proactive planning, modeling, and tracking state legislative efforts.
That is correct, but it needs to be translated into an actionable playbook. Below is a practical framework that is suitable for sophisticated taxpayers, multistate businesses, and advisors managing multijurisdictional exposure.
Step 1: Assign accountability to a single owner
The survey highlights the need for a designated point person who follows state legislative news, monitors the status of tax legislation, and develops a holistic multistate model.
This role should be clearly owned. When responsibility is diffuse, modeling becomes reactive and inconsistent.
Step 2: Build a state-by-state conformity dashboard
For each relevant state, track:
general IRC conformity posture (rolling/static/selective),
whether the state has completed a revenue study (or plans one),
whether conformity legislation is expected in the next session (yes/depends/no),
whether guidance is expected (yes/depends/no), and
whether guidance is expected to be issued all at once or in parts.
The survey provides the macro-level distribution; your dashboard should convert it into your own state footprint.
Step 3: Identify the OBBBA provisions that move your numbers
Start with the provisions Bloomberg Tax flagged as “top of mind” (including §163(j), §168(k), §174A, and §951A). Then add any OBBBA items that materially affect your tax base, attributes, or timing.
Step 4: Model three outcomes per key provision, per key state
For each relevant state and provision, maintain three scenarios:
full conformity,
partial conformity or modified conformity (common in practice), and
decoupling.
Early modeling does not need perfect precision. It needs to identify magnitude, directionality, and sensitivity.
Step 5: Treat “depends” as a volatility indicator
Where a state signals “depends” on legislation or guidance, treat it as a live risk area. The survey shows “depends” is a meaningful category for both legislative activity and guidance issuance.
Step 6: Stress-test estimated payments and cash planning
Where scenario modeling indicates material exposure swings, evaluate:
whether estimated payments should be adjusted,
whether reserves are warranted (where applicable),
and whether cash needs should be buffered for potential retroactive changes or delayed conformity.
Step 7: Maintain parallel schedules where decoupling is likely
For depreciation, interest limitation, and capitalization-related provisions, it is typically more efficient to maintain clean parallel schedules early than to reconstruct after the fact.
Step 8: Separate “administrative guidance” from “statutory change”
Guidance can clarify filing expectations and administrative interpretations, but it does not always resolve statutory conformity questions—particularly where the legislature has not acted. Maintain two separate trackers:
legislative enactments (statute-level), and
agency guidance (forms, notices, FAQs, instructions).
Step 9: Prepare for amended return workflows
If key states act retroactively or late in the filing cycle, amended returns may be required for technical correctness or to claim benefits. That possibility should be operationalized (data capture, approvals, sign-offs) rather than treated as an ad hoc issue.
Step 10: Monitor states with automatic decoupling triggers
If a state automatically decouples from significant federal changes pending legislative action, the taxpayer should treat that state as a high priority for monitoring and modeling, even if the state generally follows the IRC. The executive summary highlights this approach and notes Maryland’s expectation of legislative decisions in the 2026 session.
Step 11: Document assumptions and update cadence
Given that the survey anticipates staggered guidance, your internal model should reflect:
as-of dates for assumptions,
source citations (statutes, guidance, legislative trackers),
and planned update intervals (weekly during session, monthly otherwise).
Step 12: Align internal stakeholders on the reality of transitional nonuniformity
The executive summary quotes practitioners emphasizing the need for clarity and resources, and it underscores the likelihood of a difficult year due to limited guidance and disparate approaches.
Stakeholders should be told explicitly: short-term fragmentation is normal after major federal change, and the organization’s objective is to manage it systematically.
9. What to expect next
Based on the survey’s themes, a realistic near-term outlook looks like this:
Near term: continued revenue impact studies, selective legislative activity, and piecemeal agency guidance.
Mid term (as 2026 sessions proceed): more conformity legislation, with targeted decoupling where revenue costs are high.
Longer term: a new, more stable equilibrium—still nonuniform across states, but at least administrable once states finalize their positions.
The executive summary suggests that early-moving states that choose to decouple from costly accelerated deduction provisions may make it easier politically for later states to do the same.
Conclusion
OBBBA is federal law. State adoption is a separate process governed by state conformity rules, fiscal constraints, and administrative implementation capacity.
The Bloomberg Tax survey shows states are actively evaluating OBBBA, but legislative action has been limited to date, and guidance—though expected in many jurisdictions—will be uneven in timing and approach.
For taxpayers, the immediate goal should not be to predict every state outcome perfectly. It should be to manage uncertainty through a living conformity model, disciplined data capture, and scenario-based forecasting that can be updated as states publish legislation and guidance.