{"model":"capital-gains","specVersion":"1.0.0","specUrl":"/api/v1/models/capital-gains/spec","inputs":{"ordinaryTaxableIncome":{"kind":"float","min":0,"max":1000000},"shortTermGain":{"kind":"float","min":0,"max":500000},"longTermGain":{"kind":"float","min":0,"max":2000000},"filingStatus":{"kind":"choice","values":["single","married"]}},"arrayInputs":{},"constraints":["Gains only — loss netting and carryforwards are out of scope. NIIT MAGI is approximated by taxable income + gains, which can understate NIIT near the threshold (spec exclusion)."],"sentinels":[],"facts":[{"id":"irs.brackets.single.top-of-10pct.2026","label":"Top of 10% ordinary bracket, single (vintage marker for the TY2026 table)","value":12400,"period":"TY2026","source":"IRS TY2026 inflation adjustments (Rev. Proc. 2025-32)"},{"id":"irs.brackets.mfj.top-of-10pct.2026","label":"Top of 10% ordinary bracket, MFJ (vintage marker for the TY2026 table)","value":24800,"period":"TY2026","source":"IRS TY2026 inflation adjustments (Rev. Proc. 2025-32)"},{"id":"irs.ltcg.zero-rate-top.single.2026","label":"LTCG maximum zero-rate amount, single (§1(h), §1(j)(5))","value":49450,"period":"TY2026","source":"IRS Rev. Proc. 2025-32, §.03 Maximum Capital Gains Rate"},{"id":"irs.ltcg.zero-rate-top.mfj.2026","label":"LTCG maximum zero-rate amount, married filing jointly (§1(h), §1(j)(5))","value":98900,"period":"TY2026","source":"IRS Rev. Proc. 2025-32, §.03 Maximum Capital Gains Rate"},{"id":"irs.niit.rate","label":"Net investment income tax rate","value":0.038,"period":"2013+ (IRC §1411, permanent)","source":"IRC §1411; IRS Topic 559 (Net Investment Income Tax)"},{"id":"irs.niit.threshold.single","label":"NIIT MAGI threshold, single (statutory, not inflation-indexed)","value":200000,"period":"2013+ (IRC §1411, permanent)","source":"IRC §1411(b); IRS Topic 559"},{"id":"irs.niit.threshold.mfj","label":"NIIT MAGI threshold, married filing jointly (statutory, not inflation-indexed)","value":250000,"period":"2013+ (IRC §1411, permanent)","source":"IRC §1411(b); IRS Topic 559"}],"disclaimer":"Illustrative planning model, not financial advice. Outputs follow the published model spec exactly; read the spec for assumptions and exclusions before relying on any number."}