Official estimates of Washington's millionaires tax revenue, by fiscal year

What this chart asks

How much does each official estimate expect Washington's 9.9% tax on income over $1 million to collect each year?

Why it is shown this way

• A line per estimate shows how forecasts rose from March to September and lets readers hover each year's value; a bar mark with a color encoding would stack the estimates, which would wrongly add them together.
• The y axis starts at zero so year-to-year differences are not exaggerated.

Chart annotations

These markers provide relevant context for interpreting the chart. Their timing or position does not, by itself, establish causation.

First payments due April 2029

2029

FY2029 is the first year with collections.

Data and accessibility

Download chart data · Open accessible table · Download PNG · Download SVG

Dataset wa-millionaires-tax-revenue-estimates, analysis gross-estimates-by-fy

Sources

This chart draws on the sources of the dataset versions it visualizes.

Washington millionaires tax (ESSB 6346): official revenue estimates by fiscal year

1. Multiple Agency Fiscal Note Summary, ESSB 6346 (2026), Tax on millionaires, OFM Fiscal Note package 77653 Fiscal note gross "Tax on Income" line and whole-bill net revenue by fiscal year, FY2026-2035.

   Retrieved October 21, 2026. Public record (Washington State government work). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Government. Prepared by the Department of Revenue and published by the Office of Financial Management for the Legislature in March 2026. States its assumption that affected taxpayers do not reduce taxable income.

2. Fiscal Impact Statement for Initiative 645, Office of Financial Management (July 2026) Revenue lost by fiscal year if I-645 passes (Table 1).

   Retrieved October 21, 2026. Public record (Washington State government work). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Government. Required by RCW 29A.72.025 and printed in the voters' pamphlet. Covers SFY2027-2031 only and excludes effects that depend on future legislative action.

3. Washington State Economic and Revenue Forecast, September 2026 (Vol. LXII, No. 3), Economic and Revenue Forecast Council Individual Income Tax 2027-29 biennium forecast, June and September (Table 3.7); General Fund-State detail by fiscal year (Table 3.9).

   Retrieved October 21, 2026. Public record (Washington State government work). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Government. ERFC is the state's official, bipartisan revenue forecaster; its forecast is the legal basis for the state budget. Forecast adopted September 25, 2026.

4. Revenue Review, September 25, 2026, Economic and Revenue Forecast Council Fair Start for Kids Account forecast by fiscal year (5% of prior-year income-tax collections): FY2030 $175.2 million, FY2031 $251.6 million; June-to-September revisions.

   Retrieved October 21, 2026. Public record (Washington State government work). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Government. Official ERFC presentation of the September 2026 revenue forecast.

5. Outlook for the Enacted 2026 Supplemental Omnibus Operating Budget (ESSB 5998), April 22, 2026, Economic and Revenue Forecast Council NGF-O projected ending balance by fiscal year and biennium.

   Retrieved October 21, 2026. Public record (Washington State government work). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Government. The four-year balanced-budget outlook required by RCW 43.88.055, adopted by ERFC.

6. Enacted 2026 Supplemental Budget Outlook Methodology, April 22, 2026, Economic and Revenue Forecast Council Revenue legislation counted in the outlook (ESSB 6346: -$46,400 thousand in 2025-27, +$2,309,180 thousand in 2027-29); non-mandatory FY2029 expenditures for free school meals ($140 million) and city and county fiscal health ($200 million).

   Retrieved October 21, 2026. Public record (Washington State government work). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Government. Methodology document accompanying the adopted outlook.

7. Revenues for 2025-27 and 2027-29 are still lower than expected when 2026 budget was adopted, but income tax revenue estimates are increased going forward, Washington Research Council (Sept. 25, 2026) September 2026 income-tax forecast by biennium ($3.503 billion 2027-29, $9.435 billion 2029-31) and change from June.

   Retrieved October 21, 2026. All rights reserved (quoted under fair use). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Advocacy group. Business-funded nonpartisan research group that has published analysis critical of the income tax; here it only restates ERFC forecast figures, which match ERFC Table 3.7 for 2027-29.

8. New brief: I-645: Repealing the State Individual Income Tax, Washington Research Council (Sept. 22, 2026) States that no current appropriations rely on the revenue and that the current outlook assumes $2.698 billion of income-tax revenue in 2027-29.

   Retrieved October 21, 2026. All rights reserved (quoted under fair use). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Advocacy group. Business-funded nonpartisan research group; it takes no position on I-645 in this brief.

9. 2026 General Election Voters' Pamphlet, Initiative Measure No. IP26-645, Washington Secretary of State Arguments for and against I-645 and rebuttals, written by each campaign committee.

   Retrieved October 21, 2026. Public record (Washington State government work). Figures quoted with attribution; source file linked, not rehosted.

   Reliability: Party to the dispute. Has a stake in this finding. The Secretary of State prints the statements as submitted; each argument is written by the committee for or against the measure and is not fact-checked by the state.

10. No on 645 campaign home page Campaign wording of the $13 billion claim.

    Retrieved October 21, 2026. All rights reserved (quoted under fair use). Figures quoted with attribution; source file linked, not rehosted.

    Reliability: Party to the dispute. Has a stake in this finding. Official site of the committee opposing I-645, funded mostly by labor unions (PDC).

11. Post by Rep. Pramila Jayapal (@PramilaJayapal) on X, Sept. 26, 2026 Jayapal's "$300 billion tax break" statement. Free copy

    Retrieved October 21, 2026. All rights reserved (quoted under fair use). Figures quoted with attribution; source file linked, not rehosted.

    Reliability: Party to the dispute. Has a stake in this finding. Personal campaign account of the U.S. representative for WA-07, who opposes I-645. x.com blocks automated reading; the archived copy of X's own embed record shows the same text and that the post was not edited.

12. Heywood says I-645 fiscal impact statement is premature, vows court challenge, Seattle Red (July 19, 2026) Brian Heywood quoted on K-12 funding.

    Retrieved October 21, 2026. All rights reserved (quoted under fair use). Figures quoted with attribution; source file linked, not rehosted.

    Reliability: News report. Conservative talk-radio station website; quotes Heywood from an on-air interview on The Jason Rantz Show.

13. The millionaires tax is on the WA ballot this fall. Both sides make their case, KUOW (Oct. 8, 2026) Interview transcript excerpts with Rian Watt (No) and Jaime Herrera Beutler (Yes).

    Retrieved October 21, 2026. All rights reserved (quoted under fair use). Figures quoted with attribution; source file linked, not rehosted.

    Reliability: News report. Seattle public radio station (NPR member); edited transcript of its Soundside program.

Limitations

• Every value is a static projection; no tax has been collected yet (first payments April 2029).
• ERFC's FY2030 and FY2031 values are FactHub's split of ERFC's biennial totals, using ERFC's 5% Fair Start transfers.
• Only the fiscal note projects beyond FY2031.