---
title: "QSBS (§1202) qualified-small-business-stock gain exclusion"
method: POST
path: "/v1/tax/qsbs-exclusion"
tags: ["Tax"]
---

# QSBS (§1202) qualified-small-business-stock gain exclusion

`POST /v1/tax/qsbs-exclusion`

## Request

- Base URL: `https://api.numeratica.com`
- URL: `https://api.numeratica.com/v1/tax/qsbs-exclusion`
- Auth: one of:
  - HTTP bearer
  - API key in header `X-API-Key`

Computes the IRC §1202 exclusion on a sale of qualified small-business stock — the exclusion percentage by acquisition vintage (legacy 50/75/100% for stock held >5 years) or holding-period tier (OBBBA-amended, for stock acquired after 2025-07-04: 50% at ≥3 years, 75% at ≥4, 100% at ≥5), the excluded and taxable gain under the greater-of-$10M ($15M OBBBA) or 10×-basis per-issuer cap, the 28%-rate tax on the included portion (capped at the incremental ordinary tax), NIIT on the taxable gain, the §57(a)(7) 7% AMT preference on partial exclusions, and the saving versus a plain sale. Statutory parameters are grounded to §1202; deterministic; not tax advice.

## Request body

- QSBSExclusionRequest
  - `acquisition_date` string, required: YYYY-MM-DD; drives the vintage / applicable-date test.
  - `holding_period_years` number, required: Years the stock was held.
  - `basis` number, required: Cost basis (10× basis is part of the per-issuer cap).
  - `gain` number, required: Total long-term gain on the sale.
  - `gross_assets_at_issuance` number, required: Aggregate gross assets at issuance (≤$50M legacy / $75M OBBBA to qualify).
  - `filing_status` 'single' | 'mfj' | 'mfs' | 'hoh', required
  - `tax_year` 2025 | 2026, required
  - `other_income` number: Other ordinary income (positions the excess LTCG + NIIT).

## Response `200`

The exclusion, tax on the included gain, and the saving vs a plain sale

- QSBSExclusionResponse
  - `result_id` string
  - `engine_version` string
  - `inputs` QSBSExclusionRequest
    - `acquisition_date` string, required: YYYY-MM-DD; drives the vintage / applicable-date test.
    - `holding_period_years` number, required: Years the stock was held.
    - `basis` number, required: Cost basis (10× basis is part of the per-issuer cap).
    - `gain` number, required: Total long-term gain on the sale.
    - `gross_assets_at_issuance` number, required: Aggregate gross assets at issuance (≤$50M legacy / $75M OBBBA to qualify).
    - `filing_status` 'single' | 'mfj' | 'mfs' | 'hoh', required
    - `tax_year` 2025 | 2026, required
    - `other_income` number: Other ordinary income (positions the excess LTCG + NIIT).
  - `result` object
    - `eligible` boolean: False if gross assets exceed the limit or the holding period is too short.
    - `exclusion_percent` number: 0, 0.50, 0.75, or 1.00.
    - `per_issuer_cap` number: Greater of the dollar cap or 10× basis.
    - `eligible_gain` number: Gain within the cap.
    - `excluded_gain` number: eligible_gain × exclusion_percent (out of income).
    - `section_1202_gain` number: Included eligible gain, taxed as 28%-rate gain.
    - `excess_gain` number: Gain beyond the cap, taxed as a regular LTCG.
    - `section_1202_tax` number: 28%-rate tax on section_1202_gain (capped at incremental ordinary tax).
    - `excess_ltcg_tax` number: 0/15/20 tax on the excess gain.
    - `niit` number: §1411 NIIT on the taxable gain.
    - `total_tax` number
    - `amt_preference` number: §57(a)(7): 7% of excluded gain for 50%/75% exclusions.
    - `effective_rate` number: total_tax / gain.
    - `tax_without_qsbs` number: The whole gain at regular LTCG + NIIT.
    - `savings_versus_no_qsbs` number: tax_without_qsbs − total_tax (can be slightly negative for a low-income partial-exclusion seller).
  - `disclaimer` string

## Other responses

- `400`: Invalid request
- `401`: Missing or invalid API key.
- `405`: Method not allowed
- `429`: The key's per-minute request budget is exceeded. Retry after the delay in the Retry-After header.
- `503`: A dependency (e.g. the key store) is temporarily unavailable, or the request exceeded its compute deadline. Retryable.

---

[API](https://skmtc.dev/numeratica/apis/numeratica-financial-planning-calculations-api.md) · [All operations](https://skmtc.dev/numeratica/apis/numeratica-financial-planning-calculations-api/llms.txt) · [OpenAPI document](https://skmtc.dev/numeratica/apis/numeratica-financial-planning-calculations-api/revisions/075bcfbd1ebf?raw)