Top-rate and millionaire taxes: official revenue estimates vs. actual collections
Eighteen comparisons of an official (or, for one row, independent) revenue estimate with the revenue later collected or officially re-estimated, for ten state and local taxes on high incomes enacted between 2004 and 2025: California Propositions 30 and 63, the Massachusetts 4% surtax, New York's 2009 surcharge, Maryland's 2008-10 millionaire bracket, Oregon Measure 66, Multnomah County's Preschool for All tax, Metro's Supportive Housing Services tax, and Washington's capital gains tax and 2.9% surcharge. A second table lists published estimates of how much behavioral responses reduced (or were expected to reduce) such revenue, and the behavioral assumption in Washington's 2026 income-tax estimate.
Coverage: Estimates made 2004-2025; revenue years FY2005-06 through FY2025-26
We included every top-rate or millionaire tax we could find, from 2004 on, for which both a pre-collection official estimate and a later collection figure (or official re-estimate) are published in a source we could open. Taxes with no published bracket-level collections (New Jersey 2018 and 2020, New York 2021) and New Jersey's 2004 tax (whose estimate we could not retrieve from a source) are excluded. Where one tax has several years, we include each year that has a matching estimate. The Massachusetts row includes both the Department of Revenue's forecast and the Tufts dynamic estimate, because the second is the only pre-enactment estimate in the set that cut revenue for behavioral responses.
Geography
California, Massachusetts, New York, Maryland, Oregon, Washington
Unit of observation
One estimate-vs-actual comparison for one tax and one revenue period
Update cadence
Ad hoc; updated when new collection figures are published
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.
Official revenue estimates vs. actual collections
Each row compares one revenue estimate with the revenue later collected (or officially re-estimated) for the same tax and period.
Unit of observation: One estimate-vs-actual comparison
A ratio describes the forecast error; it does not separate behavioral responses from market and economic changes.
Robustness checks
Sensitivity analysis:Ratios, verified comparisons only.
Dropping the two comparisons with secondary-source values (Oregon; Multnomah FY2025) leaves 16, of which 11 are above the estimate and 5 below, with every 2008-09 recession comparison still below.
Ratios, verified comparisons only
Question: Does the pattern hold using only comparisons whose values we read in primary or official sources?
Result: 11 of 16 verified comparisons came in above the estimate.
Operation: Filter ratio-by-comparison to verification = Verified
Counts weight taxes with more years of data more heavily (California Proposition 30 has four rows).
Result by tax
Question: For each tax, was revenue above or below its estimates?
Result: Five taxes came in above every estimate, four below every estimate (three of them in the 2008-09 recession), and Washington's capital gains tax was mixed.
Question: How much revenue have studies found behavioral responses remove from taxes like these?
Result: Measured erosion ranges from about 1.5% (New Jersey, migration only) and 8.5% (Multnomah, migration only) to 45.2% in year one and 60.9% within two years (California Proposition 30). Washington's estimate assumes 0%.
The measures differ: share of the windfall from a rate increase (California), share of static revenue (Multnomah, New Jersey), and a projection (Tufts).
Forecast vs. actual
Each forecast beside the value later observed by a saved
analysis. FactHub computes the error as the actual value minus
the forecast; for a range, it is zero inside the range and
otherwise measured from the nearest bound.
Forecast
Forecast value
Actual
Error
Percent error
Source
Proposition 30 personal income tax revenue, FY2011-12
California Legislative Analyst's Office,
California Legislative Analyst's Office Approximate date: ballot analysis for the November 2004 election. Other state reports give a higher accrual-basis figure for FY2005-06.
Proposition 63 surcharge revenue, FY2006-07
California Legislative Analyst's Office,
+433 US dollars, millions
outside the forecast range; error from the nearest bound
+24.52%
Massachusetts Taxpayers Foundation Range presented at the FY2024 consensus revenue hearing; date is the bulletin reporting it. The budget capped use at $1 billion, which was not a forecast.
4% surtax revenue (dynamic estimate), 2023
Tufts Center for State Policy Analysis,
Tufts University Center for State Policy Analysis Approximate date (January 2022). Estimate is for calendar 2023; compared with FY2024, the first full fiscal year of collections. The static estimate was $2.1 billion.
High-income surcharge revenue, SFY2009-10
New York State Division of the Budget,
Oregon Legislative Revenue Office The outcome is a revised projection ('about two-thirds' of $504 million) reported by Oregon Business; Oregon Business also reported first-year preliminary collections of $130 million against $180 million projected (72%).
Preschool for All tax revenue, FY2022
Multnomah County,
Multnomah County Approximate date: the forecast in place for FY2022 (the county does not date it). Willamette Week reported the projection as $119 million.
Preschool for All tax revenue, FY2025
Multnomah County,
Metro (Portland regional government) Approximate date: the original adopted budget. Metro's updated Fall 2024 forecast ($323.1 million) was within 0.6% of actual.
Capital gains tax revenue (gross), FY2023 (tax year 2022)
Washington Department of Revenue,
Retrieved October 21, 2026. California state government publication. Facts and figures quoted; document linked, not hosted
Reliability:
Government.
Nonpartisan fiscal adviser to the California Legislature; prepares the official ballot-pamphlet fiscal estimates. The handout reproduces the ballot-analysis estimates by year.
Retrieved October 21, 2026. California state government publication. Facts and figures quoted; document linked
Reliability:
Government.
Official ballot analysis of Proposition 55 (2016). The $7 billion figure is the state budget's assumption, not a final tabulation.
Retrieved October 21, 2026. California state government publication. Facts and figures quoted; document linked
Reliability:
Government.
State commission overseeing Proposition 63 spending; figures drawn from Governor's Budget fund condition statements, cash basis. The live site blocks automated access, so we read the archived copy.
Retrieved October 21, 2026. Publication of a private nonprofit. Facts and figures quoted; document linked
Reliability:
Advocacy group.
Business-backed fiscal research group; it opposed the surtax campaign but here reports the official hearing projections in a table. The bulletin is dated January 30, 2023.
Retrieved October 21, 2026. Massachusetts state government publication. Facts and figures quoted; page linked
Reliability:
Government.
Official DOR press release of August 9, 2024, reporting the July 24, 2024 preliminary certification; later certifications may revise it.
Retrieved October 21, 2026. University publication. Facts and figures quoted; document linked
Reliability:
Academic.
Nonpartisan university policy center, January 2022. Its dynamic estimate cut revenue about 35% for avoidance (central income elasticity of 1) and migration.
Reliability:
News report.
Business magazine item of December 16, 2010, summarizing a Statesman Journal report on an LRO presentation; the LRO document itself was not found. The original page is offline, so we link the Internet Archive copy.
Retrieved October 21, 2026. News article. Facts quoted; page linked
Reliability:
News report.
Portland weekly reporting figures from the county's annual financial report, November 21, 2025; we did not read the county report itself.
Retrieved October 21, 2026. Washington state government publication. Facts and figures quoted; document linked
Reliability:
Government.
Multi-agency fiscal note for SSB 5096 (2021), revised June 22, 2021. Gross tax = Education Legacy Trust plus Common School Construction lines; the note's $442M state total also nets out a B&O tax credit.
Retrieved October 21, 2026. Washington state government publication. Facts and figures quoted; document linked
Reliability:
Government.
Fiscal note for ESSB 5813 (2025), dated May 5, 2025; assumes about 900 taxpayers and ERFC growth, with no behavioral adjustment stated.
Retrieved October 21, 2026. Publication of a private nonprofit. Facts quoted; page linked
Reliability:
Advocacy group.
Business-supported fiscal research nonprofit that generally opposes new taxes; here it reports a figure attributed to the state's Economic and Revenue Forecast Council.
Retrieved October 21, 2026. Working paper; abstract quoted. Facts quoted; paper linked
Reliability:
Peer-reviewed study.
Peer-reviewed study using California tax-return data; Rauh is a Hoover Institution fellow. Erosion is measured against the authors' no-response counterfactual.
Retrieved October 21, 2026. Working paper hosted by OPB. Facts quoted; paper linked
Reliability:
Academic.
Economists at UNH, the Yale Budget Lab and Reed College; not yet peer reviewed. The authors call their estimate likely an upper bound.
Retrieved October 21, 2026. Washington state government publication. Facts quoted; document linked
Reliability:
Government.
Multi-agency fiscal note for ESSB 6346 (2026) as passed; states that affected taxpayers do not reduce taxable income and applies a 4.71% AGI cut for reduced IRS enforcement.
Limitations and reproducibility
Reproducible from public sources: Every estimate and actual value was typed from the cited source; build_fva.js computes the ratios, counts and per-tax summaries and writes the CSV tables and results.json. Running node build_fva.js reproduces the published files byte for byte.
Estimates and actuals are not always on the same basis. Several actuals are later official estimates rather than final tabulations (California FY2011-12 to FY2016-17, New York SFY2009-10, Oregon 2009-11), and California Proposition 63 actuals are cash-basis receipts.
Ratios are nominal and compare one estimate with one outcome; they say nothing about why the outcome differed. In particular, a ratio above 1 does not show that taxpayers did not respond to the tax, and a ratio below 1 does not show that they did.
Estimators differ (legislative analysts, revenue departments, a university center, local budget offices), and some estimates were made shortly before collections (Massachusetts FY2024, Multnomah, Metro) while others were made before enactment.
The Oregon outcome is a revised projection reported second-hand by Oregon Business, and the Multnomah FY2025 figures come from Willamette Week; these rows are marked Unverified.
The set is small (18 comparisons, 10 taxes) and not a random sample; its timing is dominated by the 2008-09 recession and the 2012-2025 market expansion.
Some forecast dates are approximate (see each forecast's note).
forecast_vs_actual.csv
text/csv · 8.2 KB (8,408 bytes)
