Bases, assumptions & sources
| Revenue source | Rate | 2025 tax base | New revenue | Primary source / method |
Methodology: revenue = rate × base for each source (static scoring, no behavioral response). The default view counts only revenue above today’s rates (the 21% corporate rate, ~26–27% top-1% bracket, 20% long-term capital-gains rate, 40% estate rate, and zero wealth/FTT); the “All collected” view adds what the current code already raises. The overall-tax-level slider multiplies every slider at once (100% = each slider’s own rate, 200% doubles all, rates cap at 100%). The corporate base ($3.1 T) is CBO’s implied effective taxable-profits base for FY2025 (≈$650B receipts at the 21% rate), smaller than BEA’s ~$3.5 T domestic pre-tax profits because of credits and deductions. Top-1% / 0.1% bases are that group’s income above its cutoff, scaled from IRS SOI Tax Year 2023 to 2025 and stripped of realized capital gains to avoid double-counting with the capital-gains slider. The wealth-tax base ($50 T) is US household net worth above a ~$50M exemption — the top ~0.1% of households — per the Fed’s Z.1/SCF. UBI denominator: 269M US adults 18+ (Census Bureau Vintage 2024 estimates).