FactHub curated dataset

Washington's $1 million-plus earners: IRS income data 1997-2023, revenue volatility and an illustrative back-cast

IRS Statistics of Income data on Washington returns with AGI of $1 million or more (with U.S. data for the years Washington's class is missing), Washington's general fund revenue by source, and FactHub's illustrative back-cast and crash scenarios for a 9.9% tax on income above $1 million.

Coverage: Tax years 1997-2023 (IRS; WA $1M class 1997-2001 and 2010-2023); fiscal years 1998-2025 (revenue)

Node: dataset:wa-millionaire-income-irs:1

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What this dataset measures

ESSB 6346 taxes household income above $1 million. The IRS state tables are the only official, long-run record of how much income Washington's $1M+ filers report and what kind. DOR and ERFC revenue tables give the comparison with the taxes Washington already relies on.

Geography: Washington, United States
Unit of observation: Tax year and geography (IRS); state fiscal year (revenue)
Update cadence: Annual, when IRS releases a new year of state data
Curator: FactHub Research Team

Curated data tables

These related tables form this versioned dataset release. Each table has its own downloadable file and field definitions.

IRS returns in the top AGI class: Washington and U.S.

Returns, AGI and income components for the top AGI class by tax year and geography.

Unit of observation: Tax year x geography

View this table

wa_irs_1m_plus_history.csv text/csv · 9.5 KB (9,730 bytes)

12 field definitions

Field	Type	Meaning	Units	Value type
`taxYear`	integer	Tax year.	—	observed
`geography`	string	WA (Historic Table 2, Washington), US (Table 1.4) or US_HT2 (Historic Table 2, United States).	—	observed
`topClass`	string	Top AGI class in the file: '1M+' or '200k+' (WA 2002-2009).	—	observed
`allReturns`	integer	All returns in the geography.	returns	observed
`allAgiBillion`	number	AGI of all returns.	billion US dollars (nominal)	observed
`returns1mPlus`	integer	Returns in the top class.	returns	observed
`agi1mPlusBillion`	number	AGI of the top class.	billion US dollars (nominal)	observed
`wages1mPlusBillion`	number	Salaries and wages of the top class.	billion US dollars (nominal)	observed
`netCapitalGain1mPlusBillion`	number	Net capital gain (less loss) in AGI of the top class.	billion US dollars (nominal)	observed
`partnershipSCorp1mPlusBillion`	number	Partnership and S-corporation net income (less loss); from 2009.	billion US dollars (nominal)	observed
`businessIncome1mPlusBillion`	number	Business or profession net income (less loss).	billion US dollars (nominal)	observed
`sourceFile`	string	Exact IRS file for the row.	—	observed

Washington general fund revenue by source

Retail sales, B&O and state property tax revenue and total general fund-state collections by fiscal year.

Unit of observation: State fiscal year (July-June)

View this table

wa_revenue_by_source_history.csv text/csv · 9.8 KB (10,082 bytes)

6 field definitions

Field	Type	Meaning	Units	Value type
`fiscalYear`	integer	State fiscal year ending June 30.	—	observed
`retailSalesMillion`	number	Retail sales tax to the general fund.	million US dollars (nominal)	observed
`boMillion`	number	Business and occupation tax to the general fund.	million US dollars (nominal)	observed
`statePropertyMillion`	number	State property tax levy to the general fund.	million US dollars (nominal)	observed
`totalGfsMillion`	number	Total general fund-state collections (ERFC, cash).	million US dollars (nominal)	observed
`source`	string	Document and URL for each row's values.	—	observed

Illustrative back-cast of a 9.9% tax on income over $1M

FactHub illustration, not a forecast.

Unit of observation: Tax year x geography

View this table

wa_millionaires_tax_backcast.csv text/csv · 3 KB (3,091 bytes)

11 field definitions

Field	Type	Meaning	Units	Value type
`taxYear`	integer	Tax year.	—	observed
`geography`	string	WA or US.	—	observed
`returns1mPlus`	integer	Returns with AGI of $1M or more.	returns	observed
`agi1mPlusBillion`	number	AGI of $1M+ returns.	billion US dollars (nominal)	observed
`netCapitalGain1mPlusBillion`	number	Net capital gain of $1M+ returns.	billion US dollars (nominal)	observed
`excessOver1mBillion`	number	AGI above $1M per return, summed.	billion US dollars (nominal)	derived
`illustrativeTaxBillion`	number	9.9% of the excess.	billion US dollars (nominal)	estimated
`illustrativeTaxExNetCgBillion`	number	9.9% of the excess after removing net capital gain.	billion US dollars (nominal)	estimated
`agiYoYPct`	number	Change in AGI from the prior year.	percent	derived
`netCgYoYPct`	number	Change in net capital gain from the prior year.	percent	derived
`illustrativeTaxYoYPct`	number	Change in the illustrative tax from the prior year.	percent	derived

Illustrative crash scenarios

FactHub illustration, not a forecast.

Unit of observation: Scenario x baseline

View this table

wa_crash_scenarios.csv text/csv · 1.4 KB (1,404 bytes)

8 field definitions

Field	Type	Meaning	Units	Value type
`scenario`	string	Historical episode and years used.	—	observed
`baseline`	string	Official revenue estimate the drop is applied to.	—	observed
`excessBaseDropPct`	number	Drop in the excess-over-$1M base over the episode.	percent	derived
`baselineAnnualBillion`	number	Baseline annual revenue.	billion US dollars (nominal)	estimated
`revenueAfterBillion`	number	Baseline x (1 - drop).	billion US dollars (nominal)	estimated
`annualHitBillion`	number	Baseline x drop (gross base).	billion US dollars (nominal)	estimated
`exNetCgBaseDropPct`	number	Drop in the base excluding net capital gains.	percent	derived
`exNetCgAnnualHitBillion`	number	Baseline x drop excluding net capital gains.	billion US dollars (nominal)	estimated

Supporting files

Source snapshots, manifests, quality reports, documentation, and other materials used to produce or review this release.

volatility.js Transformation manifest · text/javascript · 8.3 KB (8,496 bytes)
Node.js script that computes the back-cast, crash scenarios and volatility statistics from the two curated tables. Run: node volatility.js in a folder holding both CSVs.
build_datasets.js Transformation manifest · text/javascript · 49.4 KB (50,561 bytes)
Node.js script holding every typed input value and computing the CSV tables and saved analyses for this dataset. Run: node build_datasets.js.
dataset-parts-irs.json Documentation · application/json · 40.9 KB (41,911 bytes)
The dataset's limitations, sources, tables, events, saved analyses and forecasts as JSON, as stored in this version.

Saved analyses

Year-over-year change: Washington $1M+ AGI vs. state sales tax and general fund revenue

Question: How much more does the income of Washington's $1M+ filers swing from year to year than the state's main existing revenue?

Result: Washington $1M+ AGI fell 44.6% in 2001 and 34.0% in 2022 and rose by more than half in 1998, 1999, 2012 and 2021. The general fund's worst year was -9.6% (FY2009) and retail sales tax's -12.5% (FY2009).

Operation: Percent change from the prior year in agi1mPlusBillion (WA, $1M+ class), retailSalesMillion and totalGfsMillion.

Scope: Washington; tax years for AGI, state fiscal years for revenue, 1998-2025

View this analysis

1997-2001 IRS state files count returns processed in each calendar year, a different product from the 2010+ tax-year tables.
The $1M threshold is nominal, so more returns cross it over time from inflation alone.
Sales tax is DOR GAAP-basis revenue; total general fund is ERFC cash collections.

Volatility of the $1M+ income base compared with Washington's existing taxes

Question: How large are typical year-to-year swings in each series?

Result: Typical yearly swing (standard deviation of changes): $1M+ AGI 32.9%; illustrative tax 38.37% (32.34% without capital gains); retail sales tax 5.41%; B&O 5.79%; total general fund 4.78%.

Operation: Sample standard deviation of year-over-year percent changes over all available years, plus the worst and best year and the number of declines (volatility.js).

Scope: Washington, all available years per series

View this analysis

The $1M+ series has 17 annual changes with an eight-year gap that includes the 2007-2009 recession; the revenue series have 26-27.
Revenue series include the effects of tax-law changes (for example the 2010 B&O increase), which add to their measured volatility.

Illustrative back-cast: a 9.9% tax on Washington income over $1M, 1997-2023

Question: What would a 9.9% tax on income above $1M have raised from Washington's $1M+ filers each year, and how much would it have swung?

Result: Illustration only: about $1.57B (2000) to $0.80B (2001, -49%); $7.04B (2021) to $4.40B (2022, -38%) to $3.69B (2023). Without net capital gains: -42% in 2001, -15% in 2022, +15% in 2023.

Operation: illustrativeTaxBillion = 0.099 x (agi1mPlusBillion - returns1mPlus x $1M); illustrativeTaxExNetCgBillion removes net capital gain from the excess first.

Scope: Washington $1M+ AGI class, tax years with a $1M class

View this analysis

Not a forecast. Ignores compliance, the 4.71% enforcement adjustment, the shared $1M deduction for couples, inflation indexing and any behavioral response.
Returns are not households; nominal $1M threshold in every year.

Illustrative crash scenarios for the millionaires tax

Question: If the $1M+ income base fell as it did in 2001, 2008-09 or 2022, how much revenue would the tax lose a year against official baselines?

Result: Illustration only. Income tax alone (excluding capital gains): about $0.5-0.7B a year in a 2022-style year, $1.6-2.0B in a 2001-style year, $0.8-1.0B a year over a 2007-09-style downturn. Counting all income over $1M, which is closer to total state revenue from top earners with the capital gains tax: $1.2-2.4B.

Operation: Annual hit = baseline x historical % drop in the excess-over-$1M base (gross and excluding net capital gains). Baselines: ERFC September 2026 FY2030-31 average ($4.72B) and fiscal note FY2030 ($3.732B).

Scope: Illustration for the first full years of the tax

View this analysis

Not a forecast. A future downturn may be larger or smaller and may hit wages, options or gains differently.
Baselines are themselves estimates; ERFC raised its first-year estimate 30% between June and September 2026.

Sources

IRS Statistics of Income, Historic Table 2: Individual income and tax data by state and size of adjusted gross income (Washington files, 1997-2023) Washington returns, AGI, wages, net capital gain, partnership/S-corporation and business income by AGI class; the $1M-or-more class for 1997-2001 and 2010-2023, $200,000-or-more for 2002-2009. Each row's file is in the sourceFile column.
Retrieved October 21, 2026. Public domain (U.S. government work). Public domain; values restated, files linked.

Reliability: Government. Compiled by the IRS from individual income tax returns. The 1997-2001 state files are unedited counts of returns processed in each calendar year; later files are tax-year tabulations with counts rounded to the nearest 10 from 2015.
IRS Statistics of Income, Table 1.4: All returns, sources of income, by size of adjusted gross income (U.S., 1998-2023) U.S. returns, AGI, wages, net capital gain and pass-through income for AGI of $1M or more, used to show the 2002-2009 years for which no Washington $1M class exists.
Retrieved October 21, 2026. Public domain (U.S. government work). Public domain; values restated, files linked.

Reliability: Government. National sample-based estimates from the IRS individual complete report. Net capital gain and pass-through are FactHub sums of the gain and loss columns, matching the Historic Table 2 U.S. totals within about 1% in 2010-2023.
Washington Department of Revenue, Tax Statistics, Table 3: Washington State General Fund Revenues (fiscal years 1998-2024) Retail sales, business and occupation and state property tax revenue to the general fund by fiscal year (GAAP basis, from the state's annual financial report). Each year's file is in the source column.
Retrieved October 21, 2026. Public record of a Washington state agency. Figures restated with attribution; files linked.

Reliability: Government. DOR's annual statistical report restating general fund revenue from the state's audited financial statements. FY2002 and FY2025 come from ERFC cash tables because DOR's tables for those years were not available.
Washington Economic and Revenue Forecast Council, Revenue Review, September 25, 2026 Total general fund-state collections by fiscal year, FY2005-FY2025 (current definition, cash), and the September 2026 forecast of the individual income tax used as a baseline in the crash scenarios.
Retrieved October 21, 2026. Public record of a Washington state agency. Figures restated with attribution; the PDF is linked, not hosted.

Reliability: Government. ERFC is the state's official, bipartisan revenue forecasting body. Its forecast is the basis for the budget; it published no separate risk analysis of the new income tax.
Washington Economic and Revenue Forecast Council, Economic and Revenue Forecast, June 2010 (Table 3.15) Total general fund-state collections (GF-S plus related fund, cash) for fiscal years 1998-2004.
Retrieved October 21, 2026. Public record of a Washington state agency. Figures restated with attribution; archived copy linked.

Reliability: Government. ERFC historical table under the definition used in 2010; it differs from the current definition, so FY1998-2004 totals are not spliced to FY2005 onward for year-over-year change.
OFM Fiscal Note Package 77653, ESSB 6346 (2026), tax on income over $1 million The Department of Revenue's estimate of the income tax (FY2030 $3.732B gross), used as the second baseline in the crash scenarios.
Retrieved October 21, 2026. Public record of a Washington state agency. Figures restated with attribution; the PDF is linked, not hosted.

Reliability: Government. Official fiscal note for the enacted bill. It is a static estimate: it states that affected taxpayers do not reduce taxable income.

Limitations and reproducibility

Reproducible: The curated tables hold values read from IRS, DOR and ERFC files named in each row. volatility.js recomputes the back-cast, crash scenarios and volatility statistics; build_datasets.js assembles the saved analyses.

IRS publishes no Washington $1M+ class for 2002-2009; those rows give the $200,000-or-more class, and U.S. $1M+ data stands in for the shape of the 2001-02 and 2007-09 downturns.
The 1997-2001 Washington IRS files are a different product (returns processed in a calendar year, unedited) from the 2010+ tax-year tables.
Returns are not households, and the $1M class is in nominal dollars.
The back-cast and crash scenarios are FactHub illustrations, not forecasts, and ignore behavioral responses, compliance and the law's capital-gains credit except as noted.
Revenue by source mixes DOR GAAP figures with ERFC cash figures for two years, and total general fund revenue changes ERFC definition at FY2005.

Publications using this dataset

Version details

The exact citing versions, and the version of this dataset each cites.

Article wa-millionaires-tax-volatility — version 5 (published) cites version 1
Article wa-millionaires-tax-volatility — version 4 (published) cites version 1
Chart wa-millionaire-income-vs-revenue-swings — version 1 (published) cites version 1
Briefing wa-i-645 — version 6 (published) cites version 1
Briefing wa-i-645 — version 4 (published) cites version 1