# Crypto ETF Sentinel — SEC Comment-Letter History by Issuer CIK

> Crypto ETF Sentinel — SEC Comment-Letter History by Issuer CIK is a paid API for AI agents from api.cryptoetfsentinel.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Returns the full chronological SEC ↔ issuer comment-letter history (UPLOAD/CORRESP pairs with review-intensity classification) for a single US spot crypto ETF issuer identified by SEC CIK.

## Facts

- Endpoint: GET https://api.cryptoetfsentinel.com/v1/issuers/comment-letters
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-cryptoetfsentinel-com-ef70aaac
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bOJR8lVmfhSpe5i9m5GvS

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 api-cryptoetfsentinel-com-ef70aaac
```

Example prompt: Pull the full SEC comment-letter history for the crypto ETF issuer with CIK 0001980994 — I want to see all the UPLOAD and CORRESP pairs in order and their review-intensity classifications to gauge how close they are to approval.

## When to prefer this

Use this endpoint when you need the full regulatory correspondence timeline for a specific US spot crypto ETF issuer and want to assess approval likelihood based on comment-letter cadence and review intensity. Prefer this over the activity feed endpoint when you need exhaustive per-issuer historical depth rather than a broad recent-activity snapshot.

## Known failure modes

- Invalid or non-numeric CIK returns a 400 validation error
- CIK not found in SEC EDGAR returns empty results or 404
- CIK exists but has no comment letters on record — returns empty array
- Payment not included or insufficient — returns 402 Payment Required
- Rate limiting or server overload — returns 429 or 503

## How this service works

Crypto ETF Sentinel — Full SEC ↔ issuer comment-letter history for one US spot crypto ETF issuer: UPLOAD/CORRESP pairs in order with a review-intensity profile. Comment-letter cadence is a leading indicator of approval proximity. Use when assessing how far along one filing's SEC review is. Pass the issuer's SEC CIK as cik.

## Output

A chronological list of UPLOAD/CORRESP comment-letter pairs exchanged between the SEC and the issuer, each annotated with a review-intensity classification, giving a leading indicator of the issuer's proximity to ETF approval.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "cik": "0001980994"
  }
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "cik": {
       "type": "string",
       "pattern": "^[0-9]{1,10}$",
       "description": "Zero-padded SEC CIK identifier (e.g. ``0001980994``). Optional — pass one to target a specific issuer (discover CIKs via /v1/issuers); omit to get the largest issuer by AUM."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "data"
     ],
     "properties": {
      "data": {
       "description": "The endpoint payload — type varies per route"
      },
      "meta": {
       "type": "object",
       "properties": {
        "limit": {
         "type": [
          "integer",
          "null"
         ]
        },
        "total": {
         "type": [
          "integer",
          "null"
         ]
        },
        "offset": {
         "type": [
          "integer",
          "null"
         ]
        }
       }
      },
      "error": {
       "type": [
        "string",
        "null"
       ]
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-cryptoetfsentinel-com-ef70aaac/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.cryptoetfsentinel.com](https://www.zero.xyz/host/api.cryptoetfsentinel.com/llms.txt)