> ## Documentation Index
> Fetch the complete documentation index at: https://api.unusualwhales.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> API requests use the base URL https://api.unusualwhales.com and require a bearer token in the `Authorization` header (`Authorization: Bearer <API_KEY>`). Create and manage API tokens at https://unusualwhales.com/dashboard/api.
> For live market data inside an AI tool, use the Unusual Whales MCP server at https://unusualwhales.com/public-api/mcp.
> Instructions for agents using Unusual Whales tools: https://unusualwhales.com/skill.md

# SEC 497 filings

> Receive Rule 497 prospectus filings of funds and securities issuers (forms 497, 497J and 497K) as they are processed.

**NOTE:**
This is the documentation for the websocket channel `sec:497_filings`.
Websocket access for personal use is only available through the [Advanced plan](https://unusualwhales.com/pricing?product=api).

You can find fully-functional examples that stream data from many channels here:

* Python: [https://github.com/unusual-whales/api-examples/tree/main/examples/ws-multi-channel-multi-output](https://github.com/unusual-whales/api-examples/tree/main/examples/ws-multi-channel-multi-output)
* Javascript: [https://github.com/unusual-whales/api-examples/tree/main/examples/ws-multi-channel-multi-output-nodejs](https://github.com/unusual-whales/api-examples/tree/main/examples/ws-multi-channel-multi-output-nodejs)

Connect to the websocket URI:

`wss://api.unusualwhales.com/socket?token=<YOUR_API_TOKEN>`

then `join` the `sec:497_filings` channel.

Each message carries one filing made under Securities Act Rule 497: prospectus and summary
material that a fund or securities issuer publishes. Forms 497, 497J and 497K arrive on
this one channel. Use `type` to tell them apart.

### Delivery characteristics

* **Updates are event driven.** The channel stays silent until a Rule 497 filing is
  processed. There is no heartbeat and no fixed schedule.
* **A filing with several issuers is sent once per issuer.** The messages share
  `accession_no` and differ in `issuer`, `issuer_cik`, `html_url` and `filing_link`.
* **Messages are not deduplicated.** If the same filing is published twice, you receive it
  twice. Identify a message by `accession_no` and `issuer_cik` together.
* **The channel sends nothing when you join.** Messages sent while you are disconnected are
  not replayed.
* **The channel is global only.** It covers every issuer at once. A join on
  `sec:497_filings:<TICKER>` is answered with an `{"error": "..."}` frame.

Payload format:

```
[
  "sec:497_filings",
  {
    "issuer": "BLACKROCK FUNDS",
    "html_url": "https://storage.cloud.google.com/data-fragments/sec-filings/form-497/0001193125-26-409916-BLACKROCK FUNDS-497K",
    "filing_link": "https://www.sec.gov/Archives/edgar/data/0000844779/0001193125-26-409916-index.html",
    "type": "497K",
    "issuer_cik": "0000844779",
    "accession_no": "0001193125-26-409916"
  }
]
```

### Field reference

Every field is present in every message. A value the filing does not provide is sent as an
empty string, never as `null`.

<div className="field-table">
  | Field | Type | Description |
  | - | - | - |
  | `issuer` | string | Name of the fund or securities issuer. |
  | `html_url` | string | URL of an archived HTML copy of the filing. The copy is not publicly accessible, and opening the URL asks for a Google sign-in. Use `filing_link` to open the filing. |
  | `filing_link` | string | URL of the filing's index page on SEC EDGAR. |
  | `type` | string | SEC form type: `497`, `497J` or `497K`. |
  | `issuer_cik` | string | SEC CIK of the issuer. |
  | `accession_no` | string | SEC accession number of the filing. |
</div>

The payload has the fields of the Kafka message
[`Form497`](/docs/kafka/types/Form497), published to the topic
[`sec-filings`](/docs/kafka/topics/sec-filings) under the key `form497`.