• The majority of companies in the United States are pass-through businesses. These businesses are not subject to the corporate income tax; instead, their income is reported on their owners’ tax returns and subject to the individual income tax.

• Over the past thirty years, the pass-through business sector has expanded significantly. Pass-through businesses now earn more net income than traditional C corporations and employ the majority of the private-sector workforce.

• On the federal level, pass-through businesses are subject to a top marginal tax rate of 44.6 percent. This means that, in most U.S. states, pass-through businesses can face marginal tax rates that exceed 47 percent.

• Some policymakers have expressed interest in taxing some large pass-through businesses as C corporations. However, there are strong theoretical and economic arguments for the current tax treatment of pass-through businesses, which are not subject to the problematic double tax regime faced by C corporations.

• On the flip side, some lawmakers have proposed creating a new, lower tax rate for pass-through business income. Aside from concerns that this approach would create opportunities for tax avoidance, it is also difficult to justify why income from pass-through businesses should be subject to lower tax rates than income from wages and salaries.

Major Types of Pass-through Businesses
Category	Description
Sole Proprietorship	An unincorporated business owned by a single individual. Individuals report sole proprietorship income on Schedule C of the 1040 tax form.
Partnership	An unincorporated business with multiple owners, either individuals or other businesses.
S Corporation	A domestic corporation that can only be owned by U.S. citizens (not other corporations or partnerships) and can only have up to 100 shareholders.

It is useful to contrast pass-through businesses with “C corporations,” or companies that are subject to the corporate income tax. Unlike pass-through businesses, C corporations can face up to two layers of tax on their income. First, income earned by a C corporation is taxed under the corporate income tax in the year it is earned. Then, when a C corporation distributes its income to shareholders in the form of dividends, or when the shareholders sell their stock and realize a capital gain, the income can be taxed a second time, under the individual income tax. By contrast, income earned by pass-through businesses is generally subject to one layer of tax, on the owners’ tax returns, without a second layer of tax on the business level.[2]

Another important difference between pass-through businesses and C corporations has to do with tax timing. In general, the owners of pass-through businesses are required to pay taxes on a business’s income in the same year the income is earned. This is also the case for the first layer of tax on C corporations, the corporate income tax, which is paid in the same year that a corporation earns income. However, shareholders of C corporations are able to defer the second layer of tax – the individual income tax on dividends or capital gains – until a corporation distributes its profits or until a shareholder realizes a gain.

Pass-Through Businesses are a Major Part of the U.S. Economy

The vast majority of businesses in the United States are pass-through businesses.[3] In 2014, out of the 30.8 million private business establishments in the United States, 28.3 million were pass-through businesses (Figure 1).[4]

The most common form of pass-through businesses in the United States is the sole proprietorship. There were 21.5 million sole proprietorships in 2014, accounting for 69.8 percent of all private businesses. On the other hand, C corporations are relatively uncommon. Only 2.5 million businesses filed taxes as C corporations in 2014, or 8.1 percent of all private businesses.

Figure 1

In addition, pass-through businesses are also responsible for more than half of private-sector jobs in the U.S. (Figure 2). In 2014, 57.3 percent of the U.S. private-sector workforce was employed or self-employed at a pass-through business.[5] In numerical terms, U.S. pass-through businesses employed 73.0 million people in 2014, compared to 54.3 million employees of C corporations.[6]

Within the pass-through sector, in 2014, S corporations had the most employees: 32.5 million people, or 25.5 percent of the private sector workforce. Although sole proprietorships are the most common form of business in the U.S., they accounted for only 19.6 percent of all private-sector jobs. This is because most sole proprietorships consist of one self-employed individual, without any other employees.

Figure 2

In 49 out of 50 states, pass-through businesses employ over 50 percent of the private workforce. The one exception is Hawaii, where pass-through businesses account for 49.9 percent of private-sector jobs. In four states, pass-through businesses are responsible for over 65 percent of the private-sector workforce: Montana (68.6 percent), South Dakota (66.3 percent), Idaho (65.4 percent), and Vermont (65.2 percent).

The Growth of the Pass-Through Sector

The dominance of pass-through businesses in the U.S. economy is a relatively recent phenomenon. In 1980, C corporations accounted for the overwhelming majority of U.S. business income, earning over three times as much as partnerships, S corporations, and sole proprietorships combined (Figure 3).[7]

However, the share of business income earned by pass-through businesses began to grow rapidly in the late 1980s. One important cause of this shift was the Tax Reform Act of 1986 (TRA86), which lowered the top individual income tax rate from 50 percent to 28 percent, making it more profitable than beforehand to operate as a pass-through business.[8]

By 1998, pass-through businesses had begun to earn a greater share of business income than C corporations. Since then, pass-through businesses have continued to earn more income than C corporations in every year except 2005. In 2012, pass-through businesses earned $1.63 trillion in net income, compared to $1.10 trillion of net income earned by C corporations.[9]

Figure 3

The rapid growth of the pass-through sector in recent decades is also apparent from the number of tax returns filed by different business forms (Figure 4).[10] In 1980, there were more tax returns filed by C corporations (2.2 million) than by partnerships (1.4 million) and S corporations (0.5 million) combined. By 2012, there were over four times as many returns filed by partnerships (3.4 million) and S corporations (4.2 million) as the returns filed by C corporations (1.6 million).

Overall, between 1980 and 2012, the number of pass-through businesses filing tax returns rose substantially, from 10.9 million businesses to 31.1 million. Concurrently, the share of all business tax returns filed by C corporations fell dramatically, from 16.6 percent in 1980 to 4.9 percent in 2012.

Figure 4

The fastest growth in the pass-through sector came among S corporations. The number of tax returns filed by S corporations rose by 671 percent between 1980 and 2012.

Pass-Through Businesses Can Face Substantial Marginal Tax Rates

While pass-through businesses are not subject to the corporate income tax, they face several substantial taxes on the federal, state, and local levels.

The most significant tax on U.S. pass-through businesses is the federal individual income tax, which is levied at rates ranging up to 39.6 percent. Pass-through businesses pass their income and losses directly to their owners, who include them in their gross income on Form 1040. As a result, the marginal income tax rate on a pass-through business is determined by whatever tax bracket the business’s owners fall into.

Federal Individual Income Tax Brackets and Rates, 2017
	Single Filers	Married Joint Filers	Head of Household Filers
10%	$0 to $9,325	$0 to $18,650	$0 to $13,350
15%	$9,325 to $37,950	$18,650 to $75,900	$13,350 to $50,800
25%	$37,950 to $91,900	$75,900 to $153,100	$50,800 to $131,200
28%	$91,900 to $191,650	$153,100 to $233,350	$131,200 to $212,500
33%	$191,650 to $416,700	$233,350 to $416,700	$212,500 to $416,700
35%	$416,700 to $418,400	$416,700 to $470,700	$416,700 to $444,500
39.6%	$418,400+	$470,700+	$444,500+
Source: Kyle Pomerleau, “2017 Tax Brackets,” Tax Foundation, http://taxfoundation.org/article/2017-tax-brackets. Note: Income thresholds refer to dollars of taxable income.

There are two other federal taxes that apply to pass-through businesses: the self-employment tax and the Net Investment Income Tax. Both of these taxes are dedicated toward funding Social Security and Medicare.

The federal self-employment tax applies to sole proprietorship income, as well as partnership income earned by general partners (together, these are referred to as “self-employment income”).[11] It is designed to mimic the federal payroll tax system (FICA), which applies at a rate of 15.3 percent for compensation under $127,200 and a rate of 2.9 percent on compensation above that threshold.[12] As such, individuals who make less than $127,000 in wages and self-employment income combined are subject to a 15.3 percent self-employment tax rate, while self-employment income above that threshold is taxed at 2.9 percent.

Since the 2013 tax year, the self-employment tax has also included a 0.9 percent surtax on self-employment income over $200,000 ($250,000 for joint filers), which is designed to mimic the Additional Medicare Tax.[13] Unlike the ordinary self-employment tax, this surtax applies based on household self-employment income, rather than individual self-employment income. All in all, the top self-employment tax rate is 3.8 percent.

The Net Investment Income Tax applies to partnership income earned by limited partners, as well as S corporation income earned by “passive shareholders,” as well as several other sources of income.[14] It is levied at a rate of 3.8 percent, on household net investment income over $200,000 ($250,000 for joint filers).

Federal Self-Employment and Net Investment Income Taxes for a Single Filer, 2017
Self-Employment Income	Self-Employment Tax Rate	Net Investment Income	Net Investment Income Tax Rate
$0 to $127,200	15.3%	$0 to $127,200	0%
$127,200 to $200,000	2.9%	$127,200 to $200,000	0%
$200,000 +	3.8%	$200,000 +	3.8%
Note: This calculation applies to a single filer who does not earn any wages or salary.

In addition to these federal taxes, pass-through businesses are subject to state and local income taxes. Forty states and the District of Columbia levy state income taxes on pass-through businesses; the highest is California’s, with a top rate of 13.3 percent.

After all of these taxes combined, pass-through businesses can face a substantial marginal tax rate on their business income. For instance, a sole proprietor in California can be subject to a marginal tax rate as high as 51.8 percent (see table below).[15]

Top Marginal Tax Rate for a Sole Proprietorship in California, 2017
Top marginal federal income tax	39.6%
Top marginal state income tax	13.3%
Federal self-employment tax	3.8%
Adjustments for the state and local tax deduction, the deductible portion of the self-employment tax, and the Pease limitation	-4.9%
Total	51.8%
Source: Author’s calculations

The top marginal tax rate on pass-through business income varies somewhat by state, ranging from 42.6 percent in ten states to 51.8 percent in California (Figure 5). The median state has a top marginal tax rate of 47.2 percent on sole proprietorship income. Weighted by the amount of pass-through business income in each state, the mean top marginal tax rate on sole proprietorships in the United States is 47.1 percent.

Figure 5.

The Case for the Current Tax Treatment of Pass-Through Business

Because pass-through businesses play such a large role in the U.S. economy, it is likely that the taxation of pass-through businesses will be a central focus of the tax reform debate in 2017 and beyond.

One question that federal lawmakers will face over the coming months is whether to raise or lower the seven individual tax rates on ordinary income (from 10 percent to 39.6 percent), and by how much. Because these rates apply to pass-through business income, they are the most important factor in determining the amount that pass-through businesses pay in federal income taxes.

However, in recent years, there have also been proposals to make more fundamental changes to the system of taxing pass-through businesses. Some scholars have called for taxing certain pass-through businesses as C corporations, meaning that some pass-through businesses would be subject to more than one layer of tax.[16] On the flip side, some policymakers have proposed creating a maximum tax rate for pass-through business income, meaning that some pass-through income would be taxed at lower rates than wages and salaries.[17]

Both of these proposals would be a sharp break from the last century of federal tax policy. Since the enactment of the federal income tax in 1913, income from pass-through businesses has been subject to a single layer of tax, at the same rates that apply to wages, salaries, and most other personal income.[18]

In general, lawmakers should be cautious about making fundamental changes to the tax treatment of pass-through businesses. This is because the current system of taxing pass-through businesses has several important, positive qualities.

The tax treatment of pass-through businesses is largely neutral, because pass-through business income is subject to the same income tax rates as most other personal income. In other words, the income tax code neither encourages nor discourages individuals from earning income from pass-through business activity, compared to other economic activities, for the most part.[19]

As a result, the current system of taxing pass-through businesses is also fairly efficient, because it allows individuals to choose whether to participate in pass-through businesses based on the economic merits, rather than based on tax considerations. In general, most economists agree that neutral tax systems are more economically efficient than tax systems that apply higher rates to specific activities.[20]

Finally, the tax treatment of pass-through businesses is relatively equitable, because households are taxed on their pass-through business income according to their overall tax bracket. Households with high incomes pay higher marginal income tax rates on their pass-through business income.

All in all, the current system for taxing pass-through businesses is designed well. Recent proposals to change how pass-through businesses are taxed would raise issues regarding neutrality, efficiency, and equity.

Taxing Some Pass-Through Businesses as C Corporations

It is easy to see why requiring some pass-through businesses to be taxed as C corporations would be a misguided approach. The tax treatment of C corporations is highly non-neutral, because the U.S. tax code imposes two layers of tax on corporate income, leading to an especially high top marginal tax rate on income from C corporations.[21] The corporate tax code is also quite inefficient, containing several well-known features that distort business decision-making, such as the bias towards debt financing over equity financing.[22] Finally, it is uncertain whether the corporate income tax even falls primarily on corporate shareholders, or whether it is largely borne by workers, making it difficult to determine whether the tax is equitable.[23]

Proponents of this approach argue that some pass-through businesses are just as large and economically significant as C corporations, and that there is little justification for creating two separate tax regimes for similar types of businesses. There is merit to this line of argument, but instead of forcing pass-throughs into the problematic double tax regime faced by C corporations, lawmakers should work to improve the C corporate tax regime, to move it closer to a single layer of tax at the same rates that apply to wages and salaries.[24] In short, the tax code should treat C corporations more like pass-through businesses, not the other way around.

Creating a Maximum Tax Rate on Pass-Through Business Income

Meanwhile, proposals to create a new, lower rate on pass-through businesses would also raise several concerns. Lawmakers would have to justify why income from pass-through businesses should be subject to a lower tax rate than income from wages and salaries. After all, taxing pass-through business income at a lower rate would make the U.S. tax code less neutral, potentially leading individuals to invest in pass-through businesses based on tax considerations, rather than the economic merits.[25] In addition, this policy would only benefit pass-through business owners in the highest tax brackets, creating equity concerns.

Furthermore, a lower tax rate on pass-through business income could create practical difficulties for tax administration. Because such a policy creates strong incentives to categorize as much income as possible as “pass-through business income,” it would have the potential to lead to substantial tax avoidance unless accompanied by strong anti-abuse rules.[26] In 2012, Kansas adopted a similar policy – a full exclusion of pass-through business income – which significantly narrowed the state’s tax base, due in part to increased opportunities for tax avoidance.[27]

Conclusion

It is clear that pass-through businesses play a significant role in the U.S. economy. Nine out of every ten companies in the United States are pass-through businesses; combined, they earn over half of all business income, and employ the majority of the private-sector workforce.

Although pass-through businesses are not subject to the federal corporate income tax, they can still face a substantial tax burden from federal, state, and local taxes. In most U.S. states, the top marginal tax rate on pass-through business income exceeds 47 percent.

As the tax reform debate moves forward in 2017, it will be important for policymakers to consider the effects of tax reform proposals on pass-through businesses. Lawmakers should keep in mind that the current system of taxing pass-through businesses is designed well, and they should be cautious about making fundamental changes to it.

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Appendix A: The Concept of Tax Neutrality

The concept of tax neutrality can be confusing, and the term is sometimes used in different ways. This paper uses “neutral” to signify investment-consumption neutrality. The tax code is neutral toward a given class of investments if a household’s decision to undertake a marginal investment in that class is unaffected by tax considerations. Put another way, under a neutral tax code, a household would be indifferent between a) spending money on immediate consumption or b) investing the money in an asset that yields a return equal to the household’s discount rate.

To take a very easy example, the current income tax treatment of income from a bond held in a Roth IRA is perfectly neutral, because a household will pay exactly the same amount of federal income tax whether it invests $1,000 in the bond or whether it spends the money on consumption. The household’s decision about whether to consume or invest is entirely unaffected by tax considerations.

To determine whether lowering the tax rate on a given source of personal income would make the U.S. tax code more or less neutral, it is necessary to look at the overall tax treatment of that source of income under current law.

Creating a lower top rate on pass-through business income would likely be a move away from tax neutrality. This is because, under the current tax code, the tax treatment of pass-through business investment is already close to neutral. More precisely, the tax treatment of pass-through businesses would be perfectly neutral if pass-through businesses were able to expense the full cost of their capital investments. If expensing applied to all pass-through business investments, then households would be indifferent between consuming their income and investing it in a pass-through business at a normal rate of return.

By contrast, lowering the tax rate on long-term capital gains and qualified dividends would move the tax treatment of equity-financed C corporate investment closer to tax neutrality. This is because, under the current U.S. tax code, the tax treatment of corporate stock held in taxable accounts is quite far from neutral. Even with the current, lower rate schedule for long-term capital gains and qualified dividends, the top tax rate on C corporate equity is significantly higher than the top tax rate on wages and salaries, which gives households a significant incentive to consume their income, rather than investing in C corporate stock.

Appendix B: Supplemental Data on Pass-Through Businesses

FOOTNOTES:

[1] These categories do not always line up precisely with the business categories defined by state law. For instance, limited liability companies – a legal business form in all fifty states – can be classified as sole proprietorships, partnerships, S corporations, or C corporations for federal tax purposes, depending on the circumstances.