Internal Revenue Service

The Internal Revenue Service (IRS) is the United States federal tax administration agency and a bureau of the U.S. Department of the Treasury. It administers and enforces federal internal revenue laws, processes tax returns, collects federal taxes, issues refunds, provides taxpayer assistance, and oversees compliance programs across individuals, businesses, estates, tax-exempt organizations, and other taxpayers.^[1]

Institutional role

The IRS is the principal operating agency through which the federal government administers the Internal Revenue Code. Its core functions are taxpayer service, return processing, revenue collection, refund issuance, compliance examination, collection enforcement, criminal investigation of tax-related offenses, and publication of administrative guidance such as forms, instructions, notices and revenue procedures. The IRS describes its mission as providing taxpayers with service to help them understand and meet their tax responsibilities, while enforcing the law with integrity and fairness.^[1]

The agency is part of the U.S. Department of the Treasury, not an independent commission. The Treasury secretary has statutory authority to administer and enforce internal revenue laws under section 7801 of the Internal Revenue Code, and the IRS is organized to carry out those responsibilities. Section 7803 provides for a Commissioner of Internal Revenue to administer and supervise the execution and application of the internal revenue laws.^[1]

The IRS differs from financial market regulators such as the U.S. Securities and Exchange Commission and the Commodity Futures Trading Commission. Its jurisdiction is centered on federal taxation rather than securities disclosure, market integrity or derivatives oversight. However, its work directly affects financial markets because tax rules influence household saving, business investment, retirement accounts, mergers, capital gains, dividends, estate planning, municipal finance, payroll systems and cross-border reporting.

History

Federal internal taxation in the United States predates the modern income tax. During the War of 1812, Congress enacted internal taxes on items such as refined sugar, carriages, distillers and auction sales, and later repealed remaining internal taxes in 1817.^[5] The modern institutional lineage of the IRS is usually traced to the Civil War. On July 1, 1862, President Abraham Lincoln signed a revenue measure that created a permanent internal tax system and established the Office of the Commissioner of Internal Revenue within the Treasury Department. George S. Boutwell became the first commissioner on July 17, 1862.^[5]

The federal income tax enacted during the Civil War was temporary, but the revenue bureau continued to collect other internal taxes. The income tax was reinstated after ratification of the Sixteenth Amendment in 1913, which gave Congress explicit constitutional authority to levy income taxes without apportioning them among the states by population. The agency’s administrative responsibilities expanded greatly as the income tax became a central source of federal revenue.

The IRS’s current name dates to the postwar administrative reorganization of the tax bureau. The official IRS history timeline states that the Bureau of Internal Revenue officially became the Internal Revenue Service on July 9, 1953.^[5] The name change was part of a broader modernization of tax administration, including changes in taxpayer communication, processing systems and regional administration.

Legal authority and governance

The IRS’s authority is grounded in the Internal Revenue Code, Treasury regulations, court decisions, and administrative guidance. Congress enacts tax statutes; the Treasury Department issues regulations and policy direction; and the IRS administers the day-to-day system of assessment, collection and enforcement. This structure means the IRS generally does not make tax policy in the same sense as Congress, but it has significant administrative discretion in implementation, guidance, examination priorities and taxpayer service operations.

The Commissioner of Internal Revenue leads the agency. The Office of Commissioner was created by Congress on July 1, 1862.^[2] The commissioner is responsible for supervising the application of internal revenue laws, managing the agency, and overseeing its operating divisions and enforcement functions. The IRS also has chief counsel functions, information technology operations, taxpayer service units, compliance organizations and specialized divisions for large businesses, small businesses, wage and investment taxpayers, tax-exempt entities and government entities.

The IRS is subject to congressional oversight, judicial review, the Administrative Procedure Act in relevant contexts, budget appropriations, Treasury oversight and external review by entities such as the Treasury Inspector General for Tax Administration and the Government Accountability Office. Taxpayers can contest many IRS determinations through administrative appeals and, where applicable, the U.S. Tax Court, federal district courts or the Court of Federal Claims.

Revenue collection and tax system scale

The IRS is one of the most financially significant public agencies in the United States because it collects the great majority of federal government receipts. The IRS Data Book reports that, during fiscal year 2025, the agency collected $5.3 trillion in gross taxes, processed 271.4 million tax returns and other forms, and issued $638.8 billion in tax refunds.^[4] The IRS’s annual Data Book is a major public source for statistics on tax returns, collections, refunds, audits, taxpayer assistance, staffing and budget data.^[7]

Earlier data show similar scale. In fiscal year 2023, the IRS collected almost $4.7 trillion in revenue and processed more than 271.5 million tax returns.^[1] The agency’s Statistics of Income division reported that the IRS issued about $659.1 billion in tax refunds in FY 2023, assisted nearly 60.3 million taxpayers who called or visited an IRS office, and recorded more than 880.9 million visits to IRS.gov, including 303.1 million inquiries to the “Where’s My Refund?” tool.^[3]

The composition of IRS collections includes individual income taxes, employment taxes, corporate income taxes, estate and gift taxes, excise taxes and other receipts. Individual income tax withholding and estimated tax payments are particularly important to the federal revenue base. For FY 2025, the IRS reported that individual income tax withheld and tax payments totaled $2.9 trillion before refunds, while business income taxes collected before refunds totaled $486.4 billion.^[4]

Taxpayer service

Taxpayer service is a core IRS function because the U.S. tax system relies heavily on voluntary compliance: taxpayers and third parties file returns and information reports, calculate liabilities, make payments, and retain records. IRS service channels include IRS.gov, online taxpayer accounts, telephone assistance, taxpayer assistance centers, written correspondence, practitioner hotlines, forms and instructions, publications, and education programs.

Service quality can materially affect compliance costs. Individuals, small businesses and nonprofit organizations often interact with the IRS during filing season, when they need guidance on withholding, refunds, estimated tax payments, credits, amended returns, identity verification or notices. Businesses also depend on IRS systems for employer identification numbers, payroll tax deposits, information reporting, excise tax filings and resolution of account discrepancies.

The IRS’s public-facing digital role has grown over time. IRS.gov is used for forms, instructions, account access, payment tools, refund tracking and tax-law updates. The IRS reported more than 880.9 million visits to IRS.gov in FY 2023, which illustrates the importance of digital self-service as part of modern tax administration.^[3]

Enforcement and compliance

IRS enforcement activities are intended to protect the tax base and maintain confidence in voluntary compliance. The agency conducts civil examinations, information matching, underreporter programs, collection actions, promoter investigations, employment tax enforcement, international tax compliance programs and criminal investigations. Enforcement can involve correspondence audits, office audits, field examinations, summonses, liens, levies, penalties and referrals for prosecution in criminal cases.

In FY 2023, the IRS closed 582,944 tax return audits, resulting in $31.9 billion in recommended additional tax.^[1] Audit rates and enforcement priorities vary by taxpayer type, income level, issue complexity and statutory limitations. Large corporate, partnership, high-income individual and international tax matters often require specialized expertise because they may involve transfer pricing, financial products, pass-through entities, valuation questions, tax credits, tax shelters, related-party transactions and foreign reporting.

The IRS’s enforcement role has a macroeconomic dimension. The difference between taxes legally owed and taxes paid on time is commonly referred to as the tax gap. Although the tax gap is not the same as tax fraud, it captures underreporting, underpayment and nonfiling. Policymakers often debate IRS funding and enforcement on the basis of expected revenue effects, administrative burden, taxpayer rights and the distribution of audit activity.

Relationship to financial institutions and markets

The IRS is not a bank supervisor like the Office of the Comptroller of the Currency, the Federal Deposit Insurance Corporation or the Federal Reserve System. Nevertheless, banks, brokers, payment companies, fund sponsors, employers and custodians interact extensively with IRS rules. They may have obligations to file information returns, withhold tax, report interest and dividends, document foreign account holders, administer retirement account reporting, and provide forms to customers.

For investment markets, tax administration affects after-tax returns and transaction reporting. Brokerage firms and fund administrators must report items such as dividends, interest, gross proceeds, cost basis and retirement distributions. Investors use this information to complete income tax returns and calculate capital gains or losses. Tax rules also influence the design of financial products, including tax-exempt municipal securities, retirement accounts, real estate investment structures, insurance products and exchange-traded funds such as an exchange-traded fund.

The IRS also intersects with anti-money-laundering and financial-crime policy, although those functions are not identical. The Financial Crimes Enforcement Network administers major Bank Secrecy Act reporting regimes, while the IRS administers tax laws and has a Criminal Investigation division that investigates tax crimes and related financial crimes.

Modernization and funding

IRS operations depend heavily on technology because the agency processes hundreds of millions of returns and information reports each year. Modernization priorities include replacing legacy systems, improving identity verification, expanding online accounts, digitizing paper filings, improving telephone service, accelerating refund and correspondence processing, and using data analytics in compliance work.

The Inflation Reduction Act of 2022 provided long-term funding intended to modernize the IRS and improve service, enforcement and operations. The IRS published an Inflation Reduction Act Strategic Operating Plan describing modernization initiatives, and the Taxpayer First Act work was incorporated into that broader plan in April 2023.^[6][8] These initiatives include service improvements, digital tools, employee training, data security and compliance improvements.

Modernization remains a recurring policy issue because IRS performance is tied to appropriations, staffing levels, technology investment, filing-season volumes, legislative complexity and taxpayer behavior. Congress frequently changes tax law, and the IRS must implement new credits, reporting rules, withholding changes, payment systems or relief programs under tight deadlines. The agency’s effectiveness therefore depends not only on internal management but also on the complexity and stability of the tax code it administers.

Taxpayer rights and dispute resolution

Tax administration includes both enforcement powers and procedural protections. Taxpayers have rights to receive notices, challenge IRS positions, seek administrative review, retain representation, and pursue judicial remedies in appropriate cases. Many disputes begin with an IRS notice generated by return processing or information matching. If the taxpayer disagrees, the issue may proceed through correspondence, audit reconsideration, independent administrative appeals or litigation.

The Taxpayer First Act required the IRS to develop recommendations to reimagine taxpayer experience, enhance employee training and restructure the agency to increase collaboration and innovation.^[8] The law is part of a broader policy trend emphasizing taxpayer service, transparency and procedural fairness alongside enforcement.

Taxpayer rights are especially important because IRS determinations can affect refunds, penalties, liens, levies, passport certification, business cash flow and access to credit. For businesses, payroll tax disputes can be particularly consequential because employment taxes are collected from workers and remitted by employers. For individuals, refund freezes, identity-theft issues and collection actions can have immediate financial effects.

Data and public reporting

The IRS publishes extensive statistics through its Statistics of Income program. The annual Data Book provides fiscal-year information on returns filed, electronic filing, collections, refunds, taxpayer assistance, examinations, appeals, criminal investigations, budget and workforce. The IRS describes the Data Book as an annual publication containing statistical tables and organizational information on a fiscal-year basis.^[7]

These data are widely used by policymakers, researchers, tax practitioners, journalists and financial institutions. For example, filing and refund statistics provide insight into tax-season operations; collection data show the relative importance of different tax types; and enforcement data show examination activity and recommended additional tax. Because tax administration data are sensitive, public reporting is generally aggregated and subject to confidentiality rules.

Significance in U.S. public finance

The IRS is central to U.S. fiscal capacity. It supplies the federal government with the revenue needed to fund defense, Social Security, Medicare, interest on public debt, grants to states, public health programs, infrastructure, education and other federal activities. The agency’s effectiveness influences both the amount of revenue collected under existing law and the perceived fairness of the tax system.

For households and businesses, the IRS is the primary federal agency encountered in routine financial life. Annual tax filing, wage withholding, estimated payments, retirement account distributions, business deductions, charitable contributions, tax credits, capital gains and estate matters all bring taxpayers into contact with IRS rules. As a result, the IRS functions as both a revenue agency and a major administrative interface between the federal government and the private economy.