Tax

Tax-gain harvesting room + the tax of realizing a long-term gain

How much long-term capital gain can be realized at 0% then 15% (gains stack on ordinary taxable income), and — given a realize_amount — the tax of realizing it: the split across the 0%/15%/20% bands, the capital-gains tax, the incremental 3.8% NIIT once MAGI crosses the §1411 threshold (supply magi), and the rate on the next gain dollar. Reuses the tax engine's LTCG breakpoints and NIIT threshold. Deterministic; not tax advice.

post/v1/tax/gain-harvesting

Request

  • Base URL: https://api.numeratica.com
  • URL: https://api.numeratica.com/v1/tax/gain-harvesting
  • Auth: one of:
    • HTTP bearer
    • API key in header X-API-Key

Request body

tax_yearinteger required

Supported tax year (2025 or 2026).

filing_status'single' | 'mfj' | 'mfs' | 'hoh' required
taxable_incomenumber required

Ordinary taxable income (after deductions); sets where the gain stacks.

realize_amountnumber

Optional long-term gain to realize → returns the realization detail.

maginumber

Optional modified AGI; adds the 3.8% NIIT on the part of the gain above the §1411 threshold.

Example request

{
  "tax_year": 2025,
  "filing_status": "single",
  "taxable_income": 40000
}

Response

Gain-harvesting room and realization tax

result_idstring
engine_versionstring
disclaimerstring

Example response

{
  "result_id": "gh_1a2b3c4d5e6f7a8b",
  "engine_version": "gain-harvesting-1.0.0",
  "inputs": {
    "tax_year": 2025,
    "filing_status": "single",
    "taxable_income": 40000
  },
  "result": {
    "realization": {
      "marginal_rate": 0.15
    }
  }
}

Changes

No recorded changes to this operation across all 1 revision of this API.