CBO’s Projections of Realized Capital Gains Subject to the Individual Income Tax

CBO’s Projections of Realized Capital Gains

Subject to the Individual Income Tax

February 2023

▪ Newly available data indicate that capital gains realizations in 2021 were

unusually large. Those gains help explain the recent strength in receipts from

individual income taxes.

▪ In the near term, capital gains can be challenging to project because realizations

tend to fluctuate more than other economic variables or revenue sources.

▪ In the longer term, the Congressional Budget Office expects capital gains

realizations to approach their historical average relative to the size of the

economy, after adjusting for differences between historical tax rates and those in

the projection period.

▪ In CBO’s February 2023 baseline projections, capital gains realizations

decrease from an estimated high of 8.7 percent of gross domestic product

(GDP) in 2021 to a long-run average of 3.7 percent of GDP by 2033.

Summary

What Are Capital Gains, and

How Are They Taxed?

A capital gain is an increase in the value of a capital asset above what it cost its

owner to acquire or improve it. Typical capital assets include financial market

assets, such as stocks, mutual funds, and bonds; ownership in private

businesses; real estate; and antiques, jewelry, and collectibles.

Taxes on capital gains are levied when the gains are realized—that is, when a

taxpayer sells an asset. The tax is levied on the difference between the net sale

price of the asset and its cost basis. The cost basis of the asset is typically

adjusted upward for any improvement expenses and downward for any

depreciation expenses that previously reduced the taxpayer’s taxable income.

A taxpayer who sells more than one asset in a year must aggregate any gains

and losses. If that aggregation results in a net loss, the taxpayer may offset up to

$3,000 against ordinary income in the current year. The remainder of the net

capital losses may be carried over to other tax years to reduce the taxpayer’s tax

liability.

Capital Gains and Capital Gains Taxes

The tax rates that apply to capital gains vary by the type of asset and the length

of time the taxpayer held the asset before selling it.

Short-Term Gains: Realized gains on assets held for less than a year are

combined with a taxpayer’s other income and taxed at the same rate as ordinary

income. The highest statutory tax rate on ordinary income is currently 37 percent.

Long-Term Gains: Realized gains on assets held for longer than a year are

usually taxed at lower rates. The statutory rate on most long-term capital gains

and qualified dividends is 0 percent, 15 percent, or 20 percent, depending on the

taxpayer’s filing status and taxable income.

In addition, both short-term and long-term realized gains may be subject to the

net investment income tax of 3.8 percent if the taxpayer’s income exceeds a

certain threshold.

Tax Rates on Realized Capital Gains

Data on individual capital gains beginning in 1995 are available at www.cbo.gov/data/budget-economic-data#7. For data before 1995, see Congressional Budget Office, Capital Gains

Taxes and Federal Revenues (October 2002), Table 1, www.cbo.gov/publication/14077.

Realized Capital Gains as a Percentage of GDP

Realized capital gains are highly

cyclical, and they vary more from

year to year than other components

of individual income. Gains have

typically fluctuated between 2 percent

and 7 percent of GDP in recent

decades.

Processing data from the Internal

Revenue Service (IRS) indicate that

realized gains increased sharply in

2021, to 8.7 percent of GDP in CBO’s

estimate—the highest level in more

than 40 years.

How Does CBO Project Capital Gains?

To project individual income tax receipts, CBO projects taxpayers’ realizations of net

positive capital gains. That amount is the sum of all short-term and long-term capital

gains minus losses (including loss carryovers) for all taxpayers whose gains exceed

their losses.

Data on capital gains realizations reported on tax returns are available with a lag:

▪ The highest-quality data on capital gains realizations are from a nationally

representative sample of individual income tax returns collected by the IRS.

Those data are typically available about a year and a half after the end of a tax

year. CBO received data on capital gains realizations for 2020 in fall 2022.

▪ The IRS produces monthly statistics, including the amount of capital gains

realized by taxpayers, as it processes individual income tax returns. Reliable

estimates are available about 11 months after the end of a tax year. CBO

received the tabulations for 2021 in December 2022.

Realizations of Net Positive Capital Gains

CBO generally projects capital gains realizations each winter for its annual Budget and

Economic Outlook and updates those projections the following summer. Because of the

timing of data availability, CBO generally has little information about capital gains

realizations in the most recent year.

For example, when CBO made its most recent projections, it had detailed tax return

data for 2020 and some processing data for 2021, but it did not have much information

about 2022 capital gains realizations.

Data Issues and Limitations in Projecting Realized Capital Gains

January 2022

January 2023

Early Fall: Individual

income tax return data

provided final 2020

realizations.

Late Fall: Processing

data showed very

strong realizations

for 2021.

Winter/Early Spring: Tax

payments may suggest

strength or weakness in

2022 realizations.

Winter/Early Spring: Tax

payments suggested

strength in 2021

realizations.

December: Finalized Projections

for February 2023 Baseline

March: Finalized Projections

for May 2022 Baseline

In CBO’s projections for the longer term, capital gains realizations approach their historical

average relative to the size of the economy, after adjusting for differences between historical

tax rates and those in the projection period.

In the near term, however, gains are also expected to be influenced by asset values,

aggregate investment, behavioral responses to anticipated changes in tax rules, and the

current level of gains relative to their equilibrium level.

▪ If realizations are above their equilibrium level—one that is consistent with measures of the

economy—CBO expects downward pressure on capital gains in the near term. Conversely,

if realizations are below their equilibrium level, CBO expects upward pressure on capital

gains in the near term.

▪ In CBO’s February 2023 projections of realized capital gains, the near term includes 2023

and 2024. Those projections begin with 2021, the latest year for which the IRS’s processing

data are available, and then estimate subsequent years from CBO’s projections of

economic variables and expected changes in tax rates.

▪ CBO’s projections of capital gains realizations are subject to a high degree of uncertainty,

particularly about taxpayer behavior and the path of the economy and asset values.

CBO’s Methods for Projecting Realized Capital Gains

CBO’s projections of receipts from individual capital gains are available at www.cbo.gov/data/budget-economic-data#7.

CBO’s February 2023 Projections of Capital Gains Realizations

The IRS’s processing data indicate

that capital gains realizations in 2021

probably exceeded $2 trillion, or

8.7 percent of GDP—their highest

level in more than 40 years.

Those realizations were larger than

CBO expected, given the performance

of the stock market and existing data

on investment and other variables.

CBO’s February 2023 baseline

projections incorporate that new

information, which explained some of

the recent strength in individual

income taxes.

In the agency’s projections, capital

gains realizations gradually revert to

about 3.7 percent of GDP over the

next 10 years.

CBO’s projections of receipts from individual capital gains are available at www.cbo.gov/data/budget-economic-data#7.

The share of individual income tax revenues that results from capital gains

realizations is highly variable.

Receipts from capital gains accounted for about 9 percent of total individual

income tax revenue, on average, before the 2008 financial crisis; afterward, in

2010, they decreased to about 5 percent. Since then, the share of receipts from

capital gains has increased steadily.

CBO estimates that the portion of individual income tax receipts that resulted from

capital gains exceeded 14 percent in fiscal years 2021 and 2022—much higher

than is typically observed. That strength helps explain why individual income taxes

measured as a share of GDP reached a historical high in fiscal year 2022.

In CBO’s projections, tax receipts from capital gains decline as a share of

individual income tax revenues. In fiscal year 2033, about 7.3 percent of individual

income tax revenues is expected to come from capital gains realizations.

How CBO’s Projections of Capital Gains Realizations Affect

Projected Individual Income Tax Receipts

This document was prepared to enhance the transparency of the work of the

Congressional Budget Office and to encourage external review of that work. In

keeping with CBO’s mandate to provide objective, impartial analysis, the document

makes no recommendations.

James Pearce and Naveen Singhal prepared the document with guidance from

Edward Harris, John McClelland, Joseph Rosenberg, and Joshua Shakin.

Sebastien Gay and Julie Topoleski provided comments. Omar Morales and

Tess Prendergast fact-checked the document.

Jeffrey Kling reviewed the document. Rebecca Lanning edited it, and Casey Labrack

created the graphics. The document is available at www.cbo.gov/publication/58914.

CBO seeks feedback to make its work as useful as possible. Please send any

comments to communications@cbo.gov.

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