# Holdings by Security — Institutional Ownership Lookup

> Holdings by Security — Institutional Ownership Lookup is a paid API for AI agents from api.agentstools.dev, paid per call via x402, $0.06/call, status unknown (last checked 2026-09-15).

Returns all institutional holders of a given security in a quarter, with concentration metrics and quarter-over-quarter flow, identified by ticker or CUSIP; currently returns availability/deferral status for this reverse-index route.

## Facts

- Endpoint: GET https://api.agentstools.dev/holdings/security
- Price: $0.06/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/holdings-by-security-institutional-ownership-lookup-449c0349
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Oe35K4MKniIr72Fws6uoq

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 holdings-by-security-institutional-ownership-lookup-449c0349
```

Example prompt: Show me all the institutional holders of IBIT for the latest available quarter, including their concentration and any quarter-over-quarter flow changes.

## When to prefer this

Use this endpoint when you need to see all institutional holders of a specific security (identified by ticker or CUSIP) rather than all holdings of a specific manager. Prefer this over the holdings-manager route when the question is 'who owns X?' rather than 'what does manager Y own?'. Note that this reverse-index route is currently deferred on this deployment and returns an availability status rather than full holder data; use the holdings-manager route for a specific manager's crypto ETF exposure instead.

## Known failure modes

- Missing both ticker and CUSIP: returns error requiring at least one identifier
- Unknown ticker or CUSIP: returns not-found or empty holder list
- Reverse index deferred: returns availability/status object rather than holder data
- Invalid quarter date format: returns validation error
- Rate limit or payment failure: 402 payment required or 429 throttle response

## How this service works

All institutional holders of one security in a quarter, by ticker or CUSIP, with concentration and quarter-over-quarter institutional flow. This reverse index is deferred on this deployment and returns availability status; a manager's crypto ETF exposure is covered now by the holdings manager route.

## Output

A list of all institutional holders of the requested security in the specified quarter, with each holder's position size, concentration percentage, and quarter-over-quarter flow change — or, when the reverse index is deferred on this deployment, an availability/status response indicating when the data will be accessible.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "cusip": {
       "type": "string",
       "description": "Security CUSIP (9 chars)"
      },
      "ticker": {
       "type": "string",
       "description": "Security ticker, e.g. IBIT"
      },
      "quarter": {
       "type": "string",
       "description": "Quarter period-end date, ISO YYYY-MM-DD (default latest)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/holdings-by-security-institutional-ownership-lookup-449c0349/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.agentstools.dev](https://www.zero.xyz/host/api.agentstools.dev/llms.txt)