The Complex Landscape of U.S. Pass-Through Business Taxation: Navigating Reforms and Seeking Neutrality

The taxation of business income in the United States presents a labyrinthine challenge, marked by distinct treatments for different business forms and a constant evolution driven by legislative reforms. At the heart of this complexity lies the dichotomy between C corporations, traditionally subject to corporate income tax at the entity level and further taxation on shareholder dividends and capital gains, and the burgeoning pass-through businesses, which avoid entity-level taxation by channeling income directly to owners’ individual tax returns. This structural difference has profound implications for economic activity, income distribution, and the efficiency of the U.S. tax system.

The Ascendance of Pass-Through Entities

Over the past several decades, pass-through businesses have experienced a remarkable proliferation, fundamentally reshaping the American economic landscape. This sector, encompassing partnerships, S corporations, and sole proprietorships, now employs the majority of the private-sector workforce and accounts for approximately half of all business income. As of 2022, a staggering $1.6 trillion of pass-through business income was reported on individual tax returns, representing over 10 percent of total income nationwide and nearly a third of income for high-earners. This growth is intrinsically linked to historical tax advantages, primarily lower effective tax rates compared to the multi-layered taxation faced by C corporations.

The journey to this dominance began in earnest with pivotal tax reforms. The Tax Reform Act of 1986 significantly reduced the top marginal federal individual income tax rate from 50 percent to 28 percent, while the federal corporate tax rate saw a more modest reduction from 46 percent to 34 percent. This shift immediately made pass-through structures more appealing. Concurrently, legislative changes eased restrictions on S corporations, gradually raising the shareholder cap from an initial 10 to 100 by 2005, and states facilitated the growth of limited liability companies (LLCs) by allowing them to elect partnership taxation. These factors combined to create a fertile environment for pass-through growth.

Data from the IRS Statistics of Income underscores this dramatic transformation. The number of pass-through business returns nearly quadrupled, surging from 10.9 million in 1980 to 40.8 million in 2022. In stark contrast, the number of C corporations declined from 2.2 million to 1.6 million during the same period. This meant that pass-through businesses escalated from representing 83.4 percent of all business returns in 1980 to a commanding 96.3 percent in 2022. S corporations, in particular, demonstrated explosive growth, increasing almost tenfold from just over half a million in 1980 to nearly 5.3 million by 2022. Nonfarm sole proprietorships remained the most prevalent, rising from 8.9 million to almost 30 million, accounting for 73.2 percent of business returns in 2022. The share of individual filers reporting sole proprietorship income steadily climbed from 9.5 percent in 1980 to 19.2 percent in 2022, reflecting the growing entrepreneurial spirit and flexibility these structures offer.

Beyond Small Businesses: The Scale of Pass-Throughs

While often colloquially linked with small enterprises, pass-through businesses span a broad spectrum of sizes. Census Bureau data from 2023 reveals that while 80 percent of pass-through businesses employ between 1 and 99 workers, a significant portion — more than 6.7 million employees, or roughly 7.5 percent of total pass-through employment — work for firms with 500 or more employees. This highlights that many large, complex operations also opt for pass-through status.

The rise of the gig economy has further propelled the growth of non-employer businesses, reinforcing the perception of pass-throughs as primarily small. However, the critical distinction lies in the institutional framework of C corporations, which remain the dominant form for publicly traded companies due to their ability to raise capital from a vast pool of domestic and foreign shareholders. S corporations face explicit limitations on shareholder numbers and residency, while only a select few partnerships, such as master limited partnerships in finance and energy, are publicly traded. Consequently, startup companies with aspirations of public offerings typically favor the C corporation structure.

Globally, the scale of the U.S. pass-through sector is exceptionally large. Most other developed countries feature a greater prevalence of C corporations. A 2009 survey comparing six major countries found Germany to be one of the few with a similarly expansive pass-through business landscape, underscoring the unique nature of the American approach.

Geographic and Sectoral Dominance

Pass-through businesses are not merely a significant economic force; they are integral to the U.S. labor market across virtually all states and industries. Six out of ten private-sector workers are either employed by or self-employed through pass-through firms. While this dominance is nationwide, its intensity varies. States like Montana, Wyoming, Idaho, South Dakota, Louisiana, and Vermont see pass-through businesses accounting for an especially large share—roughly 67 to 73 percent—of private-sector jobs. In contrast, states such as Hawaii, Iowa, Delaware, Massachusetts, and Tennessee show a slightly lower, though still majority, share of 52 to 57 percent.

Sectorally, pass-through firms lead employment across a wide array of industries, particularly within the service sector. They employ over two-thirds of the workforce in agriculture, real estate, education, arts and entertainment, construction, health care, accommodation and food services, and professional services. C corporations, conversely, tend to be more concentrated in capital-intensive or highly consolidated industries like utilities, company management, information, finance and insurance, and manufacturing.

Tax Policy: A Chronology of Influence

The growth and subsequent stabilization of the U.S. pass-through sector are intimately tied to major federal income tax policy shifts.

• Tax Reform Act of 1986: As noted, this act significantly altered the attractiveness of business forms by reducing individual income tax rates more aggressively than corporate rates, thus incentivizing the pass-through structure.
• Post-1986 Period: Subsequent years saw fluctuations, with top individual income tax rates rising to between 35 percent and 39.6 percent, while the corporate tax rate settled at 35 percent.
• The Tax Cuts and Jobs Act (TCJA) of 2017: This landmark legislation introduced sweeping changes.
  • Corporate Rate Cut: The federal corporate tax rate was slashed from 35 percent to 21 percent, a move aimed at enhancing U.S. competitiveness and mitigating the double taxation of corporate income. The top integrated tax rate on corporate income distributed as dividends fell from about 56 percent to 47 percent, making the U.S. more competitive internationally, though still above average for OECD countries.
  • Individual Rate Adjustments: While individual income tax rates were also cut, the reduction in the top rate from 39.6 percent to 37 percent was relatively minor compared to the corporate rate cut.
  • Section 199A Deduction: To provide comparable tax relief for pass-through businesses, the TCJA introduced Section 199A, allowing individuals to deduct up to 20 percent of qualified business income (QBI) from various pass-through entities. This deduction was designed to reduce marginal tax rates on this income, aiming for "tax parity." However, it came with complex limitations to prevent abuse, distinguishing QBI from labor income and imposing restrictions on specified service businesses and high-income households.
  • Other TCJA Provisions: The act also capped the deduction for state and local taxes (SALT) at $10,000, leading many states to implement pass-through entity taxes (PTETs) as workarounds. It capped pass-through business losses, required five-year amortization of domestic research and development (R&D) expenses, and limited interest deductibility, alongside allowing immediate expensing for short-lived assets.
• The One Big Beautiful Bill Act (OBBBA) of 2025: Enacted to address the sunsetting provisions of the TCJA, the OBBBA largely preserved and, in some cases, expanded the tax advantages for pass-through businesses.
  • Permanent Extensions: It permanently extended the TCJA’s individual income rates, the Section 199A deduction (at 20 percent), full expensing for short-lived assets, and domestic R&D expensing, along with a less stringent interest limitation.
  • Section 199A Enhancements: The OBBBA added a minimum deduction of $400 for Section 199A and increased the phase-in range for upper-income limitations by $25,000 for single filers ($50,000 for joint filers).
  • SALT Cap Adjustment: The SALT deduction cap was temporarily raised to $40,000 through 2029 for taxpayers with income below $500,000, offering relief to some pass-through businesses not utilizing PTETs.
  • New Expensing: It temporarily introduced expensing for certain structures used in manufacturing and production.
  • Itemized Deduction Cap: Conversely, it increased taxes for filers in the 37 percent bracket by capping the value of itemized deductions at 35 percent.

Economic, Fiscal, and Distributional Impacts of Section 199A

The Section 199A deduction has been a focal point of debate regarding its economic, fiscal, and distributional consequences. Proponents argue it stimulates investment and employment, fostering economic activity. Critics contend that it primarily encourages businesses to reclassify income or restructure, rather than generating new economic growth, and disproportionately benefits the wealthy while significantly adding to federal deficits. Research by Treasury economists in 2021 found limited evidence of either increased investment or business reorganization directly attributable to the deduction.

According to Tax Foundation modeling of the OBBBA, the Section 199A deduction is indeed one of the more pro-growth features, projected to boost long-run GDP by 0.5 percent. However, it is also a costly provision, estimated to reduce federal revenue by $740 billion over the next decade under conventional measurements. Dynamically, accounting for economic growth, the net revenue reduction is smaller, at $429 billion. This suggests a relatively lower "bang for the buck" compared to policies like full expensing.

Distributionally, the deduction’s benefits are skewed towards high-income households, reflecting the concentration of pass-through business income among top earners. Tax Foundation analysis indicates that taxpayers in the 90th to 95th percentile of earnings benefit most, with an estimated 0.8 percent increase in after-tax income in 2026, rising to 1.1 percent by 2034. For the bottom quintile, the increase is a more modest 0.1 percent in 2026 and 0.4 percent in 2034. However, the deduction’s guardrails for upper-income households do temper the benefits at the very top of the income distribution. These distributional findings also feed into broader academic discussions on income inequality, with some scholars, like Auten and Splinter, suggesting that previous studies may have overstated the rise in inequality since the 1980s by not fully accounting for the shift of business income reporting from corporate to individual tax returns.

Challenges: Tax Avoidance and Compliance Burden

The current pass-through tax system, particularly with the added complexity of Section 199A, creates significant incentives for tax avoidance and imposes substantial compliance costs.

• Relabeling and Tax Avoidance: The preferential treatment of business income relative to labor income, exacerbated by the 199A deduction, incentivizes taxpayers to reclassify wages as business income to reduce overall tax liability. This is particularly relevant given that labor income is subject to payroll and social insurance taxes not applicable to capital income. Features like multi-tiered ownership structures and the "carried interest" preference further blur the lines between capital and labor, increasing the appeal of pass-through forms for tax minimization. The distinction between "specified service businesses" (which face deduction limitations) and other businesses also creates incentives for reclassification.
• Compliance Complexity: The U.S. pass-through tax system is notoriously complex. Partnership rules, with their flexible tax allocation provisions, offer unique opportunities for structuring income and losses that are unavailable to corporate entities, but also add immense complexity. The Schedule K-1, used for reporting partnership income, is widely regarded as one of the most intricate tax forms, often leading to income mismatches, filing errors, and delays.
• High Compliance Costs: The annual cost of complying with the federal tax code exceeds an estimated $536 billion (nearly 1.8 percent of GDP) as of 2025, with a majority stemming from complex business filings. Complying with the main individual income tax return (Form 1040) alone costs about $147 billion, with over half of that attributed to returns reporting pass-through business income. Business income tax returns for pass-through entities (e.g., Form 1120-S for S corporations, Form 1065 for partnerships) contribute another $96 billion to the $126 billion total for business tax compliance. The Section 199A deduction itself adds over $19 billion in compliance costs due to its intricate forms and schedules, which can take over 24 hours per filer to complete.
• The Tax Gap and Non-Compliance: Pass-through businesses exhibit higher rates of non-compliance compared to C corporations. This is partly due to less third-party information reporting and minimal withholding, both of which are linked to lower compliance rates. The IRS estimates a $194 billion tax gap due to underreporting of individual income tax on pass-through business income for 2022. A significant portion of this ($117 billion) originates from nonfarm sole proprietorship income, where noncompliance rates can exceed 50 percent, compared to the 18 percent gross tax gap percentage for partnerships and S corporations. Expanding tax benefits and adding complexity in these high-noncompliance categories exacerbates both avoidance incentives and enforcement risks.
• International Comparison: Other developed countries often adopt simpler approaches. Many OECD nations, including the UK, Canada, and Australia, streamline reporting by emphasizing entity-level filing. Germany operates a transparent partnership system where the primary filing responsibility rests with the partnership, easing the burden on individual partners. Estonia and Latvia offer even more radical simplicity by taxing profits only when distributed to owners, eliminating pass-through taxation altogether and applying a single, straightforward corporate tax structure to all businesses.

Options for Reform: Seeking Simplicity and Neutrality

Despite the stability offered by the OBBBA’s permanent extensions, the current tax treatment of pass-through businesses remains fraught with complexity and non-neutrality. Reforms are urgently needed to simplify the rules and promote a more level playing field across business forms.

• Incremental Reforms:

  • Reforming Section 199A: Scott Greenberg proposed replacing the existing QBI deduction limits with an investment-based limit. This would allow a deduction of 100 percent of QBI up to a fixed dollar amount, or a 20 percent deduction limited by the "adjusted basis of business property" (essentially undeducted investment costs) multiplied by a set rate of return. This approach aims to reduce abuse and differentiate eligible activities more effectively, especially now that OBBBA has expanded expensing for many assets.
  • Senator Ron Wyden’s Proposals: Senator Wyden (D-OR) has repeatedly introduced legislation targeting the pass-through deduction and partnership rules. His 2021 proposal for Section 199A would phase out the deduction above $400,000 of taxable income, eliminate limitations for specified service businesses, and disallow it for married taxpayers filing separately and for trusts. This proposal, estimated to raise about $30 billion annually, would primarily affect high-income earners but would arguably increase complexity. Wyden’s legislation in 2021 and 2025 also sought to restrict partnership flexibility in shifting income, losses, and debt, and to expand the 3.8 percent net investment income tax (NIIT) to include active pass-through business income. While he projected these changes could raise over $727 billion, the NIIT expansion alone was estimated to generate $258 billion over a decade, though potentially reducing long-run GDP by 0.2 percent.
  • Other Adjustments to 199A: Eliminating the current exemption for REITs and publicly traded partnerships from wage or wage/capital limitations, or disallowing the deduction for them entirely, would simplify the provision and improve neutrality. Alternatively, limiting the deduction to eligible business income above a certain threshold (e.g., the 32 percent tax bracket) could streamline the application of high-income limitations across all claimants.
  • Doug Holtz-Eakin’s Alternative: Economist Doug Holtz-Eakin suggested equating the effective marginal tax rates on capital invested in corporate and pass-through sectors. This would involve taxing a portion of pass-through business income, based on a "deemed capital share," preferentially as qualified dividends. Initial analysis suggests this could halve the fiscal and economic impact of the existing pass-through deduction.

• Fundamental Reforms: Corporate Integration:

  • Eliminating Section 199A: A complete repeal of the pass-through deduction, while simplifying the code and raising an estimated $740 billion conventionally, would also introduce a significant economic drag, reducing long-run GDP by 0.5 percent. To mitigate this, such an elimination could be paired with revenue-neutral individual income tax rate reductions and expanded full expensing for new investments, which would boost growth and directly save about $20 billion annually in compliance costs.
  • Addressing Double Taxation: True "parity" or neutrality across business forms necessitates a more fundamental overhaul that tackles the double taxation of corporate income. Many countries address this by significantly lowering or eliminating one layer of tax, often exempting dividends or capital gains from taxation.
  • Integrated Tax Systems: A few countries have explicitly integrated their corporate and individual income taxes. Estonia and Latvia, for instance, tax distributed profits only once at the business entity level, avoiding taxes on retained earnings or dividends, creating an extraordinarily simple system applicable to all businesses. Australia and others use a credit imputation system, providing shareholders with a tax credit for corporate income taxes paid. In the U.S., proposals have included allowing corporations to deduct dividends paid, effectively treating dividends like interest.

Conclusion: Towards a Coherent Business Tax System

The extraordinary growth and unique structure of the U.S. pass-through business sector have profound implications for economic analysis and policy. Simple cross-country comparisons of corporate or individual income tax revenue can be misleading, as roughly half of U.S. business income is subject to individual, not corporate, tax. Similarly, understanding changes in income inequality requires a nuanced appreciation of the shifting composition of business income.

Ultimately, reforming the tax treatment of U.S. pass-through businesses presents a substantial opportunity to reduce taxpayer compliance costs, enhance economic growth, and foster greater fairness. The current system, a patchwork of decades of alterations and special provisions, has created a complex and non-neutral environment. A coherent business tax system that is simple, neutral across business forms, and pro-growth demands fundamental reform. The overarching goal should be a more fully integrated corporate and individual income tax code, drawing inspiration from models like Estonia and Latvia, which combine the organizational and financing advantages of C corporations with the tax neutrality of pass-throughs. Such a transformation would not only simplify tax filing, potentially saving billions in compliance costs annually, but also unlock greater economic dynamism for the nation.