# 13F Institutional Holdings by CUSIP

> 13F Institutional Holdings by CUSIP is a paid API for AI agents from x402.professorsausages.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-13).

Returns every institutional holder of a given security (identified by CUSIP) for a quarter, sorted by position value, derived from SEC 13F filings

## Facts

- Endpoint: GET https://x402.professorsausages.com/13f-holdings/security/:cusip/holders
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/13f-institutional-holdings-by-cusip-c5e9da5d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YwhQDwCzd722daN18Wjs7

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability 13f-institutional-holdings-by-cusip-c5e9da5d
```

Example prompt: Which institutional investors hold the most of 037833100 (Apple) based on the latest 13F filings — show me all holders sorted by position value?

## When to prefer this

Use this endpoint when you need to look up all institutional holders of a specific security by CUSIP and want results sorted by position value — the inverted view that EDGAR's own interface does not provide natively. Ideal for equity research, ownership concentration analysis, or tracking which major funds entered or exited a position in a given quarter.

## Known failure modes

- Invalid or unrecognized CUSIP returns empty results or 404
- CUSIP with no 13F filers in the requested quarter returns empty list
- Missing required CUSIP parameter returns 400 or validation error
- Payment not settled causes 402 response blocking data delivery
- Rate limiting or quota exceeded returns 429
- Stale data if quarter is not yet fully processed by SEC

## How this service works

Every 13F institutional holder of one security (by CUSIP) for a quarter, sorted by position value — the inverted index EDGAR doesn't have

## Output

A list of every institutional filer that reported holding the specified CUSIP in a given quarter, sorted descending by position value, including institution name, shares held, and reported value — essentially the inverted EDGAR index that maps one security to all its 13F holders.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/13f-institutional-holdings-by-cusip-c5e9da5d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.professorsausages.com](https://www.zero.xyz/host/x402.professorsausages.com/llms.txt)