Many economists and policymakers believe that the U.S. corporate tax system is in need of reform. There is, however, disagreement over why the corporate tax system needs to be reformed, and what specific policy measures should be included in a reform. To assist policymakers in designing and evaluating corporate tax proposals, this report (1) briefly reviews the current U.S. corporate tax system; (2) discusses economic factors that may be considered in the corporate tax reform debate; and (3) presents corporate tax reform policy options, including a brief discussion of current corporate tax reform proposals. The current U.S. corporate income tax system generally taxes corporate income at a rate of 35%. This tax is applied to income earned domestically and abroad, although taxes on certain income earned abroad can be deferred indefinitely if that income remains overseas. The U.S. corporate tax system also contains a number of deductions, exemptions, deferrals, and tax credits, often referred to as "tax expenditures." Collectively, these provisions reduce the effective tax rate paid by many U.S. corporations below the 35% statutory rate. In 2011, the sum of all corporate tax expenditures was $158.8 billion. The significance of the corporate tax as a federal revenue source has declined over time. At its post-WWII peak in 1952, the corporate tax generated 32.1% of all federal tax revenue. In 2010, the corporate tax accounted for 8.9% of federal tax revenue. The decline in corporate revenues is a combination of decreasing effective tax rates, an increasing fraction of business activity that is being carried out by pass-through entities (particularly partnerships and S corporations, which are not subject to the corporate tax), and a decline in corporate sector profitability. A particular aspect of the corporate tax system that receives substantial attention is the 35% statutory corporate tax rate. Although the U.S. has the world's highest statutory corporate tax rate, the U.S. effective corporate tax rate is similar to the Organization for Economic Co-operation and Development (OECD) average. Further, the U.S. collects less in corporate tax revenue relative to Gross Domestic Production (GDP) (1.9% in 2009) than the average of other OECD countries (2.8% in 2009). This report discusses a number of economic considerations that may be made while evaluating various corporate tax reform proposals. These might include analyses of the likely effect on households of certain reforms (also known as incidence analysis). Policymakers might also want to consider how certain corporate tax provisions contribute to the allocation of economic resources, choosing policies that promote an efficient use of resources. Other goals of corporate tax reform may include designing a system that is simple to comply with and administer, while also promoting competitiveness of U.S. corporations. Commonly discussed corporate tax reforms include policies that would broaden the tax base (i.e., eliminate tax expenditures) to finance reduced corporate tax rates. Concerns that the U.S. corporate tax system inefficiently imposes a "double tax" on corporate income has led some to consider an integration of the corporate and individual tax systems. The treatment of pass-through income-business income not earned by C corporations-has also received considerable attention in tax reform debates. How the U.S. taxes income earned abroad, and the possibility of moving to a territorial tax system, have emerged as important issues. Both the Obama Administration and the House Committee on Ways and Means Chairman David Camp have released tax reform proposals that would change the current tax treatment of U.S. multinationals.

Congress has long been concerned with ensuring that contributions for which tax deductions are claimed directly benefit charitable activities. Private foundations, a traditional arrangement that allows donations to non-active charitable entities, typically pay grants out of earnings on donated assets. Another arrangement that is growing rapidly is the donor advised fund (DAF). A taxpayer contributes to a DAF, taking a tax deduction. The fund sponsor makes grants to active charities, advised by the donor. Unlike private foundations, DAFs are not required to pay out a certain proportion of assets as grants each year. DAFs have become increasingly popular in recent years, partly due to commercial funds (e.g., Fidelity) with limited traditional charitable interests. Provisions enacted in the Pension Protection Act of 2006 (P.L. 109-280) required DAF sponsors to report data on grants. The data are reported at the sponsoring organization level, where sponsoring organizations may maintain multiple individual DAF accounts. The 2006 act also directed the Treasury Department to study DAFs, with Congress expressing particular interest in issues relating to potential restrictions on deductions and minimum payout requirements. The Treasury study was released in 2011. Senator Chuck Grassley, Senate Finance chairman at the time of the 2006 legislation, has criticized the study as being "disappointing and nonresponsive." The Treasury did not recommend restrictions on deductions (such as those that apply to private foundations where grants are typically made out of earnings), appealing to the lack of legal control by the donor. However, evidence from public comments in the report and sponsor websites indicate that sponsoring organizations typically follow the donor's advice, thus suggesting that donors have effective control over donations and, in some cases, investments. Private foundations have a 5% minimum payout rate (and actual payouts are only slightly above that amount). The Treasury also did not recommend a minimum payout for DAFs, indicating that more years of data are needed. The Treasury also appealed to the higher estimated average payout rate of DAF sponsoring organizations (9.3% in 2006) as compared to foundations. This report uses 2008 data to examine the minimum payout requirement, finding results similar to those found by Treasury. The average payout rate was 13.1%. More than 181,000 individual DAF accounts were maintained by roughly 1,800 DAF sponsoring organizations. Most individual accounts were maintained by institutions with a large number of accounts (two-thirds of all DAF accounts were held by sponsoring organizations that maintained at least 500 accounts; nearly half of all DAF accounts were held by commercial DAF institutions). Assets in DAF accounts were $29.5 billion, contributions were $7.1 billion, and DAF accounts paid out $7.0 billion in grants. Because DAF accounts have heterogeneous objectives, in some cases to manage giving with high payout rates and in others to establish an asset base, a DAF sponsor can have a high average payout rate although many accounts have little or no payout. In both 2006 and 2008, a substantial share of DAF sponsoring organizations paid out less than 5% of assets each year. To provide some insight into the payout behavior of individual DAF accounts, sponsoring organizations that reportedly maintained only one DAF account in 2008 are analyzed separately. Although the average payout rate was over 10%, more than 70% of DAF sponsoring organizations with a single DAF account paid out less than 5%, and 53% had no grants. In contrast, less than 4% of sponsors with 100 or more accounts, accounting for 87% of DAF accounts, have a payout rate of less than 5%. This suggests that a minimum payout rate for sponsors would not be effective; an effective minimum payout requirement would need to be applied to individual DAF accounts.

Currently, taxpayers may be able to claim two tax credits for residential energy efficiency: one is scheduled to expire at the end of 2011, whereas the other is scheduled to expire at the end of 2016. The nonbusiness energy property tax credit (Internal Revenue Code (IRC) 25C) currently provides homeowners with a tax credit for investments in certain high-efficiency heating, cooling, and water-heating appliances, as well as tax credits for energy-efficient windows and doors. For installations made during 2011, the credit rate was 10%, with a maximum credit amount of $500. The credit available during 2011 was less than what had been available during 2009 and 2010, when taxpayers were allowed a 30% tax credit of up to $1,500 for making energy-efficiency improvements to their homes. The residential energy efficient property credit (IRC 25D), which provides a 30% tax credit for investments in properties that generate renewable energy, such as solar panels, is scheduled to remain available through 2016. Advances in energy efficiency have allowed per-capita residential energy use to remain relatively constant since the 1970s, even as demand for energy-using technologies has increased. Experts believe, however, that there is unrealized potential for further residential energy efficiency. One reason investment in these technologies might not be at optimal levels is that certain market failures result in energy prices that are too low. If energy is relatively inexpensive, consumers will not have a strong incentive to purchase a technology that will lower their energy costs. Tax credits are one policy option to potentially encourage consumers to invest in energy-efficiency technologies. Residential energy-efficiency tax credits were first introduced in the late 1970s, but were allowed to expire in 1985. Tax credits for residential energy efficiency were again enacted as part of the Energy Policy Act of 2005 (P.L. 109-58). These credits were expanded and extended as part of the American Recovery and Reinvestment Act of 2009 (ARRA; P.L. 111-5). The Section 25C credit was again extended, at a reduced rate, and with a reduced cap, through 2011, as part of the Tax Relief, Unemployment Insurance Reauthorization, and Job Creation Act of 2010 (P.L. 111-312). Although the purpose of residential energy-efficiency tax credits is to motivate additional energy efficiency investment, the amount of the investment resulting from these credits is unclear. Purchasers investing in energy-efficient property for other reasons-for example concern about the environment-would have invested in such property absent tax incentives, and hence stand to receive a windfall gain from the tax benefit. Further, the fact that the incentive is delivered as a nonrefundable credit limits the provision's ability to motivate investment for low- and middle income taxpayers with limited tax liability. The administration of residential energy-efficiency tax credits has also had compliance issues, as identified in a recent Treasury Department Inspector General for Tax Administration (TIGTA) report. There are various policy options available for Congress to consider regarding incentives for residential energy efficiency. One option is to let the existing tax incentives expire as scheduled. A second option would be to extend or modify the current tax incentives. S. 3521, the Family and Business Tax Cut Certainty Act of 2012, would extend the 25C credit for two years-2012 and 2013. Another option would be to replace the current tax credits with a grant or rebate program-the Home Star Energy Retrofit Act of 2010 (H.R. 5019 / S. 3177 in the 111th Congress), for example. Grants or rebates could be made more widely available, and not be limited to taxpayers with tax liability. Enacting a grant or rebate program, however, would have additional budgetary cost.

The majority of energy produced in the United States is derived from fossil fuels. In recent years, however, revenue losses associated with tax incentives that benefit renewables have exceeded revenue losses associated with tax incentives benefitting fossil fuels. As Congress evaluates the tax code and various energy tax incentives, there has been interest in understanding how energy tax benefits under the current tax system are distributed across different domestic energy resources. In 2010, fossil fuels accounted for 78.0% of U.S. primary energy production. The remaining primary energy production is attributable to nuclear electric and renewable energy resources, with shares of 11.2% and 10.7%, respectively. Primary energy production using renewable energy resources includes both electricity generated using renewable resources, including hydropower, as well as renewable fuels (e.g., biofuels). The value of federal tax support for the energy sector was estimated to be $19.1 billion in 2010. Of this, roughly one-third ($6.3 billion) was for tax incentives that support renewable fuels. Another $6.7 billion can be attributed to tax-related incentives supporting various renewable energy technologies (e.g., wind and solar). Targeted tax incentives supporting fossil energy resources totaled $2.4 billion. This report provides an analysis of the value of energy tax incentives relative to primary energy production levels. Relative to their share in overall energy production, renewables receive more federal financial support through the tax code than energy produced using fossil energy resources. Within the renewable energy sector, relative to the level of energy produced, biofuels receive the most tax-related financial support. The report also summarizes the results of recently published studies by the Energy Information Administration (EIA) evaluating energy subsidies across various technologies. According to data presented in the EIA reports, the share of direct federal financial support for electricity produced using coal, natural gas and petroleum, and nuclear energy resources was similar in 2007 and 2010. Between 2007 and 2010, however, the share of federal financial support for electricity produced by renewables increased substantially, and federal financial support for refined coal disappeared. Projections of the annual cost of energy-related tax provisions through 2015 show that, under current law, tax-related support for renewable fuels will effectively disappear after 2012. The amount of tax-related support for renewable electricity is also scheduled to decline over time given the recent expiration of the Section 1603 grants in lieu of tax credits program and the scheduled expiration of other tax incentives for renewable electricity, such as the production tax credit (PTC). The value of energy-related tax provisions that benefit fossil fuels is projected to remain relatively constant over time, under current law, as most provisions that benefit fossil fuels are permanent Internal Revenue Code (IRC) provisions.

The federal budget deficit has exceeded $1 trillion annually in each fiscal year since 2009, and deficits are projected to continue. Over time, unsustainable deficits can lead to reduced savings for investment, higher interest rates, and higher levels of inflation. Restoring fiscal balance would require spending reductions, revenue increases, or some combination of the two. Policymakers have considered a number of options for raising additional federal revenues, including a carbon tax. A carbon tax could apply directly to carbon dioxide (CO2) and other greenhouse gas (GHG) emissions, or to the inputs (e.g., fossil fuels) that lead to the emissions. Unlike a tax on the energy content of each fuel (e.g., Btu tax), a carbon tax would vary with a fuel's carbon content, as there is a direct correlation between a fuel's carbon content and its CO2 emissions. Carbon taxes have been proposed for many years by economists and some Members of Congress, including in the 112th Congress. If Congress were to establish a carbon tax, policymakers would face several implementation decisions, including the point and rate of taxation. Although the point of taxation does not necessarily reveal who bears the cost of the tax, this decision involves trade-offs, such as comprehensiveness versus administrative complexity. Several economic approaches could inform the debate over the tax rate. Congress could set a tax rate designed to accrue a specific amount of revenues. Some would recommend setting the tax rate based on estimated benefits associated with avoiding climate change impacts. Alternatively, Congress could set a tax rate based on the carbon prices estimated to meet a specific GHG emissions target. Carbon tax revenues would vary greatly depending on the design features of the tax, as well as market factors that are difficult to predict. One study estimated that a tax rate of $20 per metric ton of CO2 would generate approximately $88 billion in 2012, rising to $144 billion by 2020. The impact such an amount would have on budget deficits depends on which budget deficit projection is used. For example, this estimated revenue source would reduce the 10-year budget deficit by 50%, using the 2012 baseline projection of the Congressional Budget Office (CBO). However, under CBO's alternative fiscal scenario, the same carbon tax would reduce the 10-year budget deficit by about 12%. When deciding how to allocate revenues, policymakers would encounter key trade-offs: minimizing the costs of the carbon tax to "society" overall versus alleviating the costs borne by subgroups in the U.S. population or specific domestic industries. Economic studies indicate that using carbon tax revenues to offset reductions in existing taxes-labor, income, and investment-could yield the greatest benefit to the economy overall. However, the approaches that yield the largest overall benefit often impose disproportionate costs on lower-income households. In addition, carbon-intensive, trade-exposed industries may face a disproportionate impact within a unilateral carbon tax system. Policymakers could alleviate this burden through carbon tax revenue distribution or through a border adjustment mechanism. Both approaches may entail trade concerns.