# SEC API, free: Company hierarchy API

> The Subsidiary API provides access to a database of all current and historical subsidiaries belonging to publicly listed companies on US stock exchanges, from 2003 to present.

SEC API's company hierarchy API on its Free plan. It costs $0.00 per 1,000 companies. It returns 2 of the 3 key fields we check: Parent, Family tree.
We rank 40 plans by price. [DanskCVRAPI's DKK 599 monthly plan](https://datacircle.dev/company-hierarchy-apis/danskcvrapi/dkk-599-monthly/llms.txt) costs the least per 1,000 companies: $0.045.
[DiscoLike](https://datacircle.dev/company-hierarchy-apis/discolike/399-monthly/llms.txt), [Bigdata.com](https://datacircle.dev/company-hierarchy-apis/bigdata-com/50-monthly/llms.txt) and [Magellan Data](https://datacircle.dev/company-hierarchy-apis/magellan-data/375-pack-25000-credits-post-v1-corporate-families/llms.txt) are the best company hierarchy API providers in our benchmark.

- This page: https://datacircle.dev/company-hierarchy-apis/sec-api/free
- [Best company hierarchy API in 2026](https://datacircle.dev/best-company-hierarchy-api.txt)
- Get it: https://sec-api.io/pricing
- Request: `POST https://api.sec-api.io/subsidiaries`
- API key: with the plan, on https://sec-api.io/pricing
- Its API docs: https://sec-api.io/docs/subsidiary-api
- Sold by: SEC API (https://sec-api.io)
- Checked: 2026-10-28

## In the answer

- Completeness: 67%
- Parent: ✓
- Family tree: ✓

## Price

- $ per 1,000 companies: $0.00
- Per: call
- Billing: free

## Aggregators

- Aggregators: none

## Overage

- Units cap: hard

## Not found

- $ per 1,000: $0.00

## In their words

- Their pitch: The Subsidiary API provides access to a database of all current and historical subsidiaries belonging to publicly listed companies on US stock exchanges, from 2003 to present.

## Data

- Freshness: 1 minute
- Keep data: no limit
- Use data: "Customers enrolled in the free \"Start\" Subscription may only use the Services for personal, non-commercial purposes and may not display or distribute Provider Data to third parties in any manner." "Customer will not, and will not allow third parties under its control to: (i) copy, modify, create a derivative work of, reverse engineer, decompile, translate, disassemble, or otherwise attempt to extract any or all of the source code of the Services [...], [...] (iii) resell or distribute any or all of the Services separately from any integrated Application, (iv) create multiple Applications or Accounts to simulate or act as a single Application or Account (respectively) or otherwise access the Services in a manner intended to avoid incurring Fees or exceed usage quotas [...]" "If Customer distributes Provider Data, Customer must state that the data was provided by Provider and provide a hyperlink to https://sec-api.io." "Customer may not publicly disclose, directly or through a third party, the results of any comparative or compatibility testing, benchmarking, or evaluation (each, a \"Test\") of the Services, unless the disclosure includes all information necessary for Provider or a third party to replicate the Test and includes the right to use the information necessary to replicate the Test. [...]" Pricing page, Usage: Personal & Startups "Personal. For startups: business internal.", Business Internal Use "Business internal only.", Enterprise & Institutions "Business internal + redistribution and reselling."

## Plan

- Pay: $0
- You get: 100 requests
- Enough for: 100 calls, once

## Speed

- Answer: in the call
- Median: 0.09 s

## The call

- You send: query. Optional: from, size, sort
- Method: POST
- Path: /subsidiaries

## About the plan

- Plan: Free
- Who can get it: anyone, no credit card required

## The 9 fields the plan's answer can hold

list ID, accession number, disclosure date, parent CIK, parent ticker, parent name, subsidiary name, subsidiary jurisdiction, total results

## SEC API's plans (4)

- [SEC API, free](https://datacircle.dev/company-hierarchy-apis/sec-api/free/llms.txt): $0.00 per 1,000, 67% complete, 1 minute
- [SEC API, $239 monthly](https://datacircle.dev/company-hierarchy-apis/sec-api/239-monthly/llms.txt): 67% complete, 1 minute
- [SEC API, $2,388 yearly](https://datacircle.dev/company-hierarchy-apis/sec-api/2388-yearly/llms.txt): 67% complete, 1 minute
- [SEC API, contact us](https://datacircle.dev/company-hierarchy-apis/sec-api/contact-us/llms.txt): 67% complete, 1 minute

## SEC API's calls for this API (1)

- `POST /subsidiaries`: [SEC API, free](https://datacircle.dev/company-hierarchy-apis/sec-api/free/llms.txt)

## SEC API's APIs (5)

- [SEC API: company funding API pricing, 6 plans](https://datacircle.dev/company-funding-apis/sec-api/free/llms.txt)
- [SEC API: company hierarchy API pricing, 4 plans](https://datacircle.dev/company-hierarchy-apis/sec-api/free/llms.txt)
- [SEC API: leadership change API pricing, 6 plans](https://datacircle.dev/leadership-change-apis/sec-api/free/llms.txt)
- [SEC API: company discovery API pricing, 6 plans, GET /exchange/{exchange}](https://datacircle.dev/company-discovery-apis/sec-api/free-get-exchange-exchange/llms.txt)
- [SEC API: company discovery API pricing, 6 plans, GET /industry/{industry}](https://datacircle.dev/company-discovery-apis/sec-api/free-get-industry-industry/llms.txt)
- [SEC API: company discovery API pricing, 6 plans, GET /sector/{sector}](https://datacircle.dev/company-discovery-apis/sec-api/free-get-sector-sector/llms.txt)
- [SEC API: company enrichment API pricing, 6 plans, GET /cik/{cik}](https://datacircle.dev/company-enrichment-apis/sec-api/free-get-cik-cik/llms.txt)
- [SEC API: company enrichment API pricing, 6 plans, GET /name/{name}](https://datacircle.dev/company-enrichment-apis/sec-api/free-get-name-name/llms.txt)
- [SEC API: company enrichment API pricing, 6 plans, GET /cusip/{cusip}](https://datacircle.dev/company-enrichment-apis/sec-api/free-get-cusip-cusip/llms.txt)
- [SEC API: company enrichment API pricing, 6 plans, GET /ticker/{ticker}](https://datacircle.dev/company-enrichment-apis/sec-api/free-get-ticker-ticker/llms.txt)

## SEC API: company hierarchy API alternatives

- [Interzoid, free API key, POST /enrich](https://datacircle.dev/company-hierarchy-apis/interzoid/free-api-key-post-enrich/llms.txt): $0.00 per 1,000, 67% complete, live

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-10-28.

- https://sec-api.io
- https://sec-api.io/docs/subsidiary-api
- https://sec-api.io/policies/terms-of-service
- https://sec-api.io/pricing