How much would the one-time billionaire tax raise, net?
Boll, Saez and Zucman (BSZ, NBER, August 2026) put the one-time tax at about $100 billion of wealth tax.
This Open Policy Analysis (OPA) adds its income tax effects to get the main estimate.
Five of the six inputs below are guesswork. Move them and the estimate updates.
This is part of an Open Policy Analysis. See more
here:
The inputs
the value the authors use
Each input is tagged by origin: data, research (a published estimate) or guesswork (set by assumption, argued for but not measured). Every input, by origin lists them all.
Outcomes
1 BSZ's headline is the wealth tax alone: $104 billion in their Table 5, here. This OPA adds the income tax effects to compare with the JR analysis. Why
Jump to a setting
Every outcome, for this setting and the four Table 5 scenarios
Wealth from the 1 July 2026 Forbes list. Leaver losses are a present value (5 years at 3%). The shaded column is the base scenario.
| Outcome | This setting |
|---|
Notes and data
Horizon. The income tax lost to leavers recurs every year they stay away. BSZ argue the losses should be temporary and give 5 years, the payment period, as an example (PDF p.27); Table 5 takes no stand on how long they last. The main estimate counts 5 years at 3% a year, the middle of the JR analysis's 1.5% to 4.5% range (BSZ give no rate). The JR analysis counts it forever: see the comparison overview.
Two departures from the workbook. (1) Its income tax loss is a literal 5%
(Tab5!H6); the explorer reads it as avoidance times the share leaving, identical at
the authors' values. (2) Table 5 deducts the phase-in (the Act's lower rate between $1B and $1.1B) in row 2 but not row 4
(Tab5!F9). The explorer copies this, so with both switches on the estimate is
higher than a consistent treatment.
Data. grid.csv (every setting),
inputs.csv (every input and its origin),
grid.js (what this page reads). The pipeline writes all three; a test
fails if grid.js differs from its output.