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13-F Institutional Holdings
x402
13-F Institutional Holdings is a paid API for AI agents from agent.massive.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).
Retrieves SEC Form 13F quarterly filings showing institutional investment manager holdings for entities with $100M+ AUM
Price / call$0.01
Success—
StatusUnknown
How this service works
SEC Form 13F filings data showing institutional investment manager holdings. Form 13F is required to be filed quarterly by institutional investment managers with at least $100 million in qualifying assets under management. Can't find what you're looking for? POST feedback to /feedback, no charge.
Output
A list of SEC Form 13F filing records for institutional investment managers, including filer CIK, filing date, and qualifying holdings data, paginated up to 1000 results per call and sortable by filing date.
Example use cases
Track hedge fund portfolio changes
“Get all 13F filings from Bridgewater Associates — CIK 0001350694 — filed between 2023-01-01 and 2024-01-01, sorted by filing date descending, so I can see how their holdings changed over 2023.”
Monitor institutional ownership before earnings
“Show me the 10 most recent 13F filings submitted to the SEC before 2024-09-30 so I can see which major institutional managers have been active this quarter.”
Research a specific manager's latest disclosure
“Look up the most recent 13F filing from Fidelity Management — CIK 0000315066 — and return just the latest one so I can see what they currently report holding.”
Technical details
Endpoint
GEThttps://agent.massive.com/stocks/filings/vX/13-FWhen to prefer
Use this endpoint when you need structured SEC 13F quarterly holdings data for institutional investment managers, especially when filtering by specific filers via CIK or date ranges. Prefer this over general SEC EDGAR search when you need clean, queryable, agent-ready JSON rather than raw filing documents. Best for systematic tracking of institutional ownership disclosures, hedge fund monitoring, or compliance research.
Side effects
- Invalid or non-existent filer_cik returns empty results or error
- Malformed date format (not YYYY-MM-DD) causes query rejection
- Limit exceeding 1000 returns validation error
- No filings matching the specified date range returns empty array
- Payment failure (x402) blocks the request if USDC balance is insufficient
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"status": "OK",
"results": [
{
"cusip": "023135106",
"period": "2024-09-30",
"put_call": null,
"filer_cik": "0001067983",
"form_type": "13F-HR",
"filing_url": "https://www.sec.gov/Archives/edgar/data/1067983/0000950123-24-011775.txt",
"file_number": "028-04545",
"filing_date": "2024-11-14",
"film_number": "241461756",
"issuer_name": "AMAZON COM INC",
"market_value": 1439212920,
"other_managers": [
"Buffett Warren E"
],
"title_of_class": "COM",
"accession_number": "0000950123-24-011775",
"investment_discretion": "DFND",
"voting_authority_none": 0,
"voting_authority_sole": 7724000,
"voting_authority_shared": 0,
"shares_or_principal_type": "SH",
"shares_or_principal_amount": 7724000
},
{
"cusip": "025816109",
"period": "2024-09-30",
"put_call": null,
"filer_cik": "0001067983",
"form_type": "13F-HR",
"filing_url": "https://www.sec.gov/Archives/edgar/data/1067983/0000950123-24-011775.txt",
"file_number": "028-04545",
"filing_date": "2024-11-14",
"film_number": "241461756",
"issuer_name": "AMERICAN EXPRESS CO",
"market_value": 311864270,
"other_managers": [
"Buffett Warren E"
],
"title_of_class": "COM",
"accession_number": "0000950123-24-011775",
"investment_discretion": "DFND",
"voting_authority_none": 0,
"voting_authority_sole": 1149942,
"voting_authority_shared": 0,
"shares_or_principal_type": "SH",
"shares_or_principal_amount": 1149942
}
],
"next_url": "https://api.massive.com/stocks/filings/vX/13-F?cursor=eyJsaW1pd...",
"request_id": "a3f8b2c1d4e5f6g7"
}
}Tags
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