Real value of the $1 million threshold at 2.5% inflation

What this dataset measures

These tables test how far the 9.9% tax on household income over $1 million (ESSB 6346, chapter 238, Laws of 2026) reaches beyond the households that pay it: how many filers sit above the line, how much their income swings from year to year, how the comparable capital gains tax has performed, and whether the $1 million threshold keeps its value over time.

Geography

Washington State

Unit of observation

Varies by table: tax year (IRS, capital gains), estimate (households), tax year by inflation scenario (threshold)

Update cadence

Ad hoc; update when IRS SOI releases tax year 2023 state data or the Department of Revenue publishes guidance on the standard-deduction adjustment

Curator

FactHub

Supporting files

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

• results.json Derived table · application/json · 20.4 KB (20,936 bytes)

  Saved-analysis result rows (chart-ready) generated from the CSV tables

• build_data.js Transformation manifest · text/javascript · 4.9 KB (4,974 bytes)

  Node.js script that extracts the IRS rows and computes the threshold projection (run: node build_data.js <folder with IRS files saved as in19.csv-in22.csv>)

Saved analyses

Sources

1. IRS Statistics of Income, Individual Income Tax State Data, tax year 2022 (22in55cmcsv.csv) Washington returns and income by AGI class, tax year 2022

   Retrieved October 14, 2026. Public domain (U.S. government work). Unrestricted; linked, not rehosted

   Reliability: Government. The IRS Statistics of Income division tabulates every individual return filed, by state and AGI class. It takes no position on Washington's tax.

2. IRS Statistics of Income, Individual Income Tax State Data, tax year 2021 (21in55cmcsv.csv) Washington returns and income by AGI class, tax year 2021

   Retrieved October 14, 2026. Public domain (U.S. government work). Unrestricted; linked, not rehosted

   Reliability: Government. The IRS Statistics of Income division tabulates every individual return filed, by state and AGI class. It takes no position on Washington's tax.

3. IRS Statistics of Income, Individual Income Tax State Data, tax year 2020 (20in55cmcsv.csv) Washington returns and income by AGI class, tax year 2020

   Retrieved October 14, 2026. Public domain (U.S. government work). Unrestricted; linked, not rehosted

   Reliability: Government. The IRS Statistics of Income division tabulates every individual return filed, by state and AGI class. It takes no position on Washington's tax.

4. IRS Statistics of Income, Individual Income Tax State Data, tax year 2019 (19in55cmcsv.csv) Washington returns and income by AGI class, tax year 2019

   Retrieved October 14, 2026. Public domain (U.S. government work). Unrestricted; linked, not rehosted

   Reliability: Government. The IRS Statistics of Income division tabulates every individual return filed, by state and AGI class. It takes no position on Washington's tax.

5. IRS SOI Tax Stats - Historic Table 2 (state data documentation) Field definitions for the state files (AGI_STUB 10 = $1,000,000 or more; N1, A00100, A00200, A01000, A26270)

   Retrieved October 14, 2026. Public domain (U.S. government work). Unrestricted

   Reliability: Government. IRS documentation of the field codes and AGI classes used in the state data files.

6. Washington State Legislature, ESSB 6346 as enacted (chapter 238, Laws of 2026) Sections 314 and 316: the $1,000,000 standard deduction and its inflation adjustment; section 1(9): the legislative estimate of who pays

   Retrieved October 14, 2026. Public domain (Washington State law). Unrestricted

   Reliability: Government. Official text of Washington law published by the Legislature's Code Reviser. The Legislature enacted the tax, but the text itself is the authoritative statement of what the law says.

7. RCW 82.87.150, capital gains tax inflation adjustments Comparison: the capital gains standard deduction is adjusted every October by the 12-month CPI change

   Retrieved October 14, 2026. Public domain (Washington State law). Unrestricted

   Reliability: Government. Official text of Washington law published by the Legislature's Code Reviser. The Legislature enacted the tax, but the text itself is the authoritative statement of what the law says.

8. RCW 82.87.040, capital gains tax rates The 2025 additional 2.9% rate on Washington capital gains over $1,000,000, a threshold RCW 82.87.150 does not adjust

   Retrieved October 14, 2026. Public domain (Washington State law). Unrestricted

   Reliability: Government. Official text of Washington law published by the Legislature's Code Reviser. The Legislature enacted the tax, but the text itself is the authoritative statement of what the law says.

9. Washington Department of Revenue, Capital Gains Tax - Tax Year 2025 Initial Collections Net capital gains tax collections and payment counts, tax years 2022-2025, as of June 9, 2026

   Retrieved October 14, 2026. Public domain (Washington State government work). Unrestricted

   Reliability: Government. The Department of Revenue administers the capital gains tax and reports collections from returns and payments. Figures are revised as refunds and amended returns arrive.

10. U.S. Census Bureau, American Community Survey 2024 1-year, table B11001 (Household Type), Washington Total Washington households: 3,168,080 (margin of error plus or minus 9,393)

    Retrieved October 15, 2026. Public domain (U.S. government work). Unrestricted

    Reliability: Government. The Census Bureau's American Community Survey estimates household counts from an annual sample; the 2024 one-year estimate has a stated margin of error.

11. Washington State Standard via The Inlander, 'WA revenue officials: Income tax will bring in more money than first expected' (Aug. 27, 2026) Department of Revenue household estimates: 21,000 (legislative fiscal note) and 25,000 (July 2026 revision)

    Retrieved October 14, 2026. News article; cited, not redistributed. Link only

    Reliability: News report. Washington State Standard reporting, republished by The Inlander, of Department of Revenue estimates presented to lawmakers. A secondary report of official figures.

Limitations and reproducibility

Reproducible: build_data.js reads the four public IRS SOI state files and regenerates every CSV; the capital gains and household figures are typed from the cited Department of Revenue page and Census table, and the threshold projection is computed by the same script from the formula in ESSB 6346 section 316.

• IRS counts are tax returns, not households; a married couple filing jointly is one return, but two single earners in one household are two returns. The tax applies per household, so return counts are only an approximation of the payer count.
• IRS adjusted gross income includes long-term capital gains, which the millionaires tax removes and replaces with Washington capital gains already taxed under chapter 82.87 RCW; the $1 million AGI class is therefore not identical to the tax's base.
• The threshold projection assumes a constant inflation rate (2%, 2.5% or 3%) and reads section 316 literally: an October adjustment in each odd year from 2029, equal to the 12-month CPI-W change, applying to that tax year. The Department of Revenue had issued no guidance interpreting section 316 as of October 2026, and section 314 calls the adjustment annual, so the department or a later Legislature could apply it differently.
• Tax year 2025 capital gains collections are initial figures as of June 9, 2026, rounded by the department to $1.5 billion.
• The household share uses the ACS 2024 one-year household count (3,168,080, margin of error plus or minus 9,393) for both payer estimates, although the tax begins in 2028.