State Conformity Considerations for Partnerships Under OBBBA

The One Big Beautiful Bill Act (OBBBA) introduced significant federal tax changes, but state adoption of those changes remains uneven. Partnerships operating across multiple jurisdictions face increased complexity as states vary in how and whether they conform to the IRC. These differences affect taxable income, partner basis, deductions, and reporting, creating state-specific compliance and planning considerations for partnerships.

Who Is Impacted

State conformity differences stemming from the OBBBA most directly affect partnerships with multi-state operations or diverse ownership profiles. These impacts are particularly relevant for:

• Partnerships operating in multiple states, especially those with activity in both rolling and nonconforming jurisdictions.
• Private equity and investment funds with portfolio companies or investments spanning several states.
• Technology, life sciences, and manufacturing partnerships with significant research and development activities.
• Capital-intensive partnerships with material interest expense.
• Partnerships holding or disposing of qualified small business stock with partners residing in different states.
• Partnerships using composite, pass-through, or withholding filing regimes for nonresident partners.

For these partnerships, differences in state conformity can affect taxable income, partner basis, cash tax obligations, and the clarity of partner-level reporting.

State Conformity Models

States generally follow one of three conformity models, each of which determines whether and when OBBBA provisions take effect for state tax purposes.

Rolling Conformity

Under rolling conformity, states automatically adopt amendments to the IRC as federal law changes. OBBBA amendments generally flow through in rolling conformity states unless the state legislature decouples from specific provisions.

For example, New York conforms to the IRC on a rolling basis for both corporate franchise tax and personal income tax. However, New York decoupled from federal bonus depreciation under IRC Sec. 168(k). Illinois and Colorado also follow rolling conformity. Federal amendments are incorporated into the starting point for Illinois and Colorado taxable income, subject to state additions and subtractions. Even in rolling states, legislatures frequently decouple from specific provisions such as the treatment of interest, deductions, and depreciation.

Fixed-Date Conformity

Fixed-date conformity states adopt the IRC as of a specific date. Federal changes enacted after that date do not apply for state tax purposes unless the state legislature updates its conformity date.

California, North Carolina, and Georgia are fixed-date conformity states. California’s conformity date is January 1, 2025, North Carolina’s conformity date is January 1, 2023, and Georgia’s conformity date is December 31, 2024. This means major federal tax changes enacted after those conformity dates are not yet recognized in California, North Carolina, and Georgia. As a result, prior federal law governs the state tax base until legislative action occurs, creating immediate differences in taxable income, deductions, and basis following major federal legislation.

Selective Conformity

Under selective conformity, states adopt only specified IRC provisions. These states may conform to certain OBBBA provisions while excluding others, resulting in highly customized state tax regimes and increased compliance complexity.

New Jersey does not broadly adopt the IRC for either its corporation business tax or gross income tax. Instead, the state selectively incorporates specific federal definitions and provisions by statute. For example, the state’s corporation business tax uses federal taxable income as its starting point but applies its own state-specific adjustments. As a result, federal amendments, including changes enacted under the OBBBA, apply in New Jersey only to the extent the state expressly references them.

Pennsylvania’s personal income tax system does not use federal taxable income as its starting point. The state uses distinct classes of income and applies its own rules for timing and deductions. Federal amendments do not automatically flow through. The General Assembly enacts specific changes before Pennsylvania adopts federal modifications. For example, although the OBBBA allows net operating loss carryforward, Pennsylvania does not allow carryforwards for personal income tax.

Alabama applies a different structure. For corporate income tax, Alabama generally follows federal rules. The state begins with federal taxable income and then applies a few state-specific additions and subtractions. For individual income tax, Alabama also starts with federal taxable income but decouples from many provisions. For example, Alabama taxes tips and overtime and applies its own rules governing deductions.

Key OBBBA Provisions Affecting Partnerships

Research and Experimental Expenditures (IRC Sec. 174/174A)

Prior to 2025, IRC Sec. 174 governed the treatment of all research and experimental (R&E) expenditures, including costs to develop new products, software, or processes. The Tax Cuts and Jobs Act required taxpayers to capitalize these expenses and amortize them over five years (15 years if the expenses were foreign). The OBBBA restores immediate expensing of domestic costs for federal income tax purposes, allowing deductions in the year incurred rather than requiring capitalization and amortization.

State conformity to IRC Sec. 174 and new IRC Sec. 174A varies widely. Some states conform and allow current expensing while others continue to require capitalization or apply their own modification rules, resulting in differences between federal and state deductions. These differences affect partnership taxable income, partner capital accounts, and outside basis calculations, often requiring state-specific adjustments on Schedule K-1.

For example, California does not conform to the OBBBA or prior federal changes affecting IRC Secs. 174 and 174A. The state retains IRC Sec. 174 language as of January 1, 2015. Although California updated its general conformity date to January 1, 2025, that update applies only to specified IRC provisions and does not broadly adopt federal research expensing changes.

Florida applies fixed-date conformity and adopts the IRC as in effect on January 1, 2025. As a result, Florida follows the prior federal capitalization and amortization rules under IRC Sec.174, requiring five year-amortization for domestic research and 15-year amortization for foreign research.

Business Interest Limitation (IRC Sec. 163(j))

IRC Sec. 163(j) limits the amount of business interest expense deductible in a given year. Prior to January 1, 2022, the limitation was determined based on a calculation using the taxpayer’s earnings before interest, taxes, depreciation, and amortization (EBITDA). For taxable years beginning on or after January 1, 2022,, the limitation was generally based on earnings before interest and taxes (EBIT). The OBBBA restores the more generous EBITDA standard at the federal level, which often permits a larger interest deduction.

States do not apply IRC Sec. 163(j) uniformly. Rolling conformity states may adopt the EBITDA approach unless they enact a decoupling adjustment and fixed-date and selective conformity states may apply EBIT or have a state-specific modification. As a result, partnerships may compute different allowable interest deductions for federal and state purposes, affecting partner basis, separately stated items, and interest expense carryforwards that often require separate tracking.

For example, California does not conform to the current federal 30% business interest limitation under IRC Sec. 163(j). California computes interest deductions under its own rules, creating federal-state differences in deductible interest.

Similarly, Georgia does not adopt the current federal business interest limitation and instead follows the version that existed before the enactment of the Tax Cut and Jobs Act.

Qualified Small Business Stock (IRC Sec. 1202)

IRC Sec. 1202 allows the exclusion of part or all of the federal income tax on gain from the sale of qualified small business stock (QSBS)subject to eligibility and holding period requirements. The OBBBA expands certain federal benefits associated with this exclusion.

States do not conform to IRC Sec.1202 uniformly. Some states decouple from the QSBS exclusion entirely, such as California and Alabama, while others such as New Jersey conform. Still other states adopt modified rules. These differences can affect partner-level gain exclusions, holding period calculations, and estimated tax payments, particularly for partnerships with owners in multiple states.

Partner-Level Reporting and Compliance

Differences in federal and state conformity also affect partnership reporting. When states differ from federal treatment, partnerships often compute separate state adjustments for income, deductions, and credits and reflect those differences in partner reporting.

In addition, state partnership audit regimes, partnership representative rules, and documentation standards vary widely, increasing the complexity of coordinated federal and state reporting.

Implications for Partnerships

Traditional compliance approaches no longer provide reliable guidance. As states deviate, partnerships now must contend with retroactive complexity, revenue triggers, temporary freezes, high-risk provisions related to R&E, interest limitations, and bonus depreciation.

Because partnerships are pass-through entities, conformity differences often arise at the entity level and ultimately affect partner-level reporting, basis, and estimated tax obligations. A single federal provision could generate multiple state-specific adjustments.

Compliance Challenges

The OBBBA’s federal changes and state-by-state decoupling have created a more complex compliance environment. Partnerships may be required to maintain separate calculations for federal taxable income under the OBBBA and for each state that has decoupled from specific provisions. These differences affect basis tracking, income and deduction allocations, and Schedule K-1 reporting.

Differences in apportionment methods, composite filing systems, and estimated tax requirements add more complexity. When states revise conformity after filing season begins, partnerships face additional administrative burden and audit risk.

Action Plan Considerations

To manage the compliance and reporting challenges created by OBBBA-related state conformity differences, partnerships should focus on the following actions:

Within 30 Days

• Identifying states in which the partnership has filing obligations and evaluating each state’s conformity position with respect to key OBBBA provisions;
• Modeling differences between federal and state treatment of research expenditures, interest limitations, and other affected items to assess impacts on taxable income and partner reporting;
• Reviewing partnership agreements to understand how tax allocation provisions address federal–state conformity differences; and
• Communicating anticipated state tax impacts to partners, including potential estimated tax adjustments.

Within 90 Days

• Maintaining dual tracking of federal and state basis, income, deductions, and carryforwards where conformity differences apply;
• Updating Schedule K-1 disclosures to clearly reflect state-specific adjustments and nonconforming treatment;
• Reviewing partnership agreements to ensure tax allocation provisions address federal-state conformity differences; and
• Engaging state tax advisors and ensure your team includes professionals monitoring state legislative developments.

Ongoing

• Monitoring legislation and guidance in all nexus states;
• Adjusting processes as needed as states enact decoupling provisions; and
• Documenting all positions by maintaining detailed workpapers for audit defense.

Looking Ahead

The traditional distinction between rolling and fixed conformity continues to erode. Conditional conformity, temporary freezes, selective adoption, and retroactive decoupling are now more common. Partnerships operating across multiple jurisdictions face an evolving compliance landscape that requires ongoing, state-by-state analysis of OBBBA provisions and flexible compliance frameworks capable of responding to continued legislative change.