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

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

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

FactHub illustration, not a forecast.

Unit of observation: Tax year x geography

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

All 45 rows 11 columns Download the file

All 45 rows

taxYear	geography	returns1mPlus returns	agi1mPlusBillion billion US dollars (nominal)	netCapitalGain1mPlusBillion billion US dollars (nominal)	excessOver1mBillion billion US dollars (nominal)	illustrativeTaxBillion billion US dollars (nominal)	illustrativeTaxExNetCgBillion billion US dollars (nominal)	agiYoYPct percent	netCgYoYPct percent	illustrativeTaxYoYPct percent
1997	WA	3372	9.439	3.326	6.067	0.601	0.271	—	—	—
1998	WA	4646	15.717	5.818	11.071	1.096	0.52	66.5	74.9	82.5
1999	WA	6263	24.28	8.394	18.017	1.784	0.953	54.5	44.3	62.7
2000	WA	6406	22.306	8.158	15.9	1.574	0.766	-8.1	-2.8	-11.8
2001	WA	4288	12.366	3.575	8.078	0.8	0.446	-44.6	-56.2	-49.2
2010	WA	5448	16.484	4.688	11.036	1.093	0.628	—	—	—
2011	WA	5873	18.595	5.676	12.722	1.259	0.698	12.8	21.1	15.3
2012	WA	8080	29.18	12.848	21.1	2.089	0.817	56.9	126.4	65.9
2013	WA	7080	22.015	6.701	14.935	1.479	0.815	-24.6	-47.8	-29.2
2014	WA	8890	30.652	11.938	21.762	2.154	0.973	39.2	78.2	45.7
2015	WA	9800	33.495	12.686	23.695	2.346	1.09	9.3	6.3	8.9
2016	WA	10600	38.425	16.232	27.825	2.755	1.148	14.7	28	17.4
2017	WA	12520	41.12	16.113	28.6	2.831	1.236	7	-0.7	2.8
2018	WA	15630	46.992	16.403	31.362	3.105	1.481	14.3	1.8	9.7
2019	WA	15890	51.162	18.111	35.272	3.492	1.699	8.9	10.4	12.5
2020	WA	19280	62.681	24.195	43.401	4.297	1.901	22.5	33.6	23
2021	WA	28930	100.006	45.075	71.076	7.037	2.574	59.5	86.3	63.8
2022	WA	21530	65.957	22.208	44.427	4.398	2.2	-34	-50.7	-37.5
2023	WA	23370	60.596	11.763	37.226	3.685	2.521	-8.1	-47	-16.2
1998	US	172004	533.469	222.591	361.465	35.785	13.749	—	—	—
1999	US	205124	653.184	271.424	448.06	44.358	17.487	22.4	21.9	24
2000	US	239685	817.414	347.554	577.729	57.195	22.787	25.1	28	28.9
2001	US	193229	579.303	184.343	386.074	38.221	19.971	-29.1	-47	-33.2
2002	US	168977	475.833	128.631	306.856	30.379	17.644	-17.9	-30.2	-20.5
2003	US	181283	535.031	162.145	353.748	35.021	18.969	12.4	26.1	15.3
2004	US	240128	762.903	271.834	522.775	51.755	24.843	42.6	67.6	47.8
2005	US	303817	1026.045	391.224	722.228	71.501	32.769	34.5	43.9	38.2
2006	US	354093	1211.268	478.289	857.175	84.86	37.51	18.1	22.3	18.7
2007	US	392220	1401.087	576.589	1008.867	99.878	42.796	15.7	20.6	17.7
2008	US	321294	1076.046	326.713	754.752	74.72	42.376	-23.2	-43.3	-25.2
2009	US	236883	726.911	150.077	490.028	48.513	33.655	-32.4	-54.1	-35.1
2010	US	280360	925.458	255.576	645.098	63.865	38.563	27.3	70.3	31.6
2011	US	300890	947.854	255.998	646.964	64.049	38.706	2.4	0.2	0.3
2012	US	392850	1378.839	454.558	985.989	97.613	52.612	45.5	77.6	52.4
2013	US	345883	1089.881	290.172	743.998	73.656	44.929	-21	-36.2	-24.5
2014	US	410298	1364.026	431.976	953.728	94.419	51.653	25.2	48.9	28.2
2015	US	439335	1455.483	451.895	1016.148	100.599	55.861	6.7	4.6	6.5
2016	US	424442	1359.841	399.253	935.399	92.605	53.078	-6.6	-11.6	-7.9
2017	US	494857	1658.925	536.912	1164.068	115.243	62.088	22	34.5	24.4
2018	US	539207	1780.074	577.044	1240.867	122.846	65.718	7.3	7.5	6.6
2019	US	556400	1735.624	537.365	1179.224	116.743	63.544	-2.5	-6.9	-5
2020	US	606710	2090.322	728.348	1483.612	146.878	74.771	20.4	35.5	25.8
2021	US	875527	3334.725	1408.112	2459.198	243.461	104.058	59.5	93.3	65.8
2022	US	804830	2725.034	868.583	1920.204	190.1	104.11	-18.3	-38.3	-21.9
2023	US	799095	2543.451	638.799	1744.356	172.691	109.45	-6.7	-26.5	-9.2

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

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.

Sources

1. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.