There are currently about 180 tax expenditures, also known as tax breaks, which can take the form of exemptions, deductions, credits, and preferential rates written into the U.S. Tax code. In 2023, those breaks totaled about $1.8 trillion. To put that in perspective, that’s more than the government spends on Social Security, Medicare and Medicaid, or defense.

Tax expenditures should be a key part of any discussion about tax reform. Many economists believe that eliminating some or all tax breaks would benefit the economy by removing market distortions and simplifying the code.

Here are eight of the most expensive tax breaks for individuals and corporations; together, they accounted for more than two-thirds of the total annual cost of tax expenditures in 2023:

1. Exclusion of pension contributions and earnings and individual retirement arrangements ($369 billion). Contributions to pension or retirement plans — such as to 401(k)s and IRAs — are not taxed as income when they are received but instead taxed in the future when the employee withdraws the funds.
2. Exclusions of and reductions on dividends and long-term capital gains ($311 billion). Income from capital gains (the profit from the sale of a property or investment) and qualified dividends (generally from shares in domestic corporations that have been held for a specified period) are taxed at a lower rate than other forms of income. Defenders argue that such preferential rates encourage the sort of investment and risk-taking that spur economic growth, but critics note that they disproportionately benefit the wealthy and encourage tax avoidance.
3. Exclusion of employer contributions for medical insurance and care ($202 billion). The premiums that employers pay for their employees’ healthcare are exempt from federal income and payroll taxes. While this tax break benefits a wide swath of Americans by reducing the after-tax cost of health insurance, it is worth more to taxpayers in higher tax brackets than to those in lower brackets.