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

# 13F Holdings Comparison API — Compare a Manager's Latest Disclosed Reports

> Compare a manager's two most recent parsable 13F reports by CIK. Inspect added, removed, and changed positions with filing provenance and clear timing limits.

Institutional investors file Form 13F on a delayed schedule. The useful question is usually not simply what a manager owns, but what changed between its two most recent disclosed reports. SEC API compares the latest two parsable 13F reports for a manager CIK and returns a row-level position diff alongside the source record for the current report.

## Capabilities

<CardGroup cols={2}>
  <Card title="Latest disclosed-report diff" icon="code-compare">
    Compare the latest two parsable 13F reports for one manager CIK. Each position is classified as added, removed, changed, or unchanged.
  </Card>

  <Card title="Share and value changes" icon="arrow-up-right-dots">
    Inspect current and prior shares and value, with absolute deltas for positions that changed.
  </Card>

  <Card title="Filing provenance" icon="file-check">
    Keep the current filing accession, source URL, filing date, and request metadata with the comparison output.
  </Card>

  <Card title="Bounded position output" icon="list-tree">
    Set a position limit when you need a concise comparison; use the underlying reports when a full filing review is required.
  </Card>
</CardGroup>

## Quick start

Compare a manager's two most recent parsable disclosed reports:

```bash theme={null}
curl -X POST "https://api.secapi.ai/v1/owners/13f/compare" \
  -H "x-api-key: $SECAPI_API_KEY" \
  -H "content-type: application/json" \
  -d '{"cik":"0001350694","limit":50}'
```

```json theme={null}
{
  "managerName": "Example Manager",
  "currentFilingDate": "2025-02-14",
  "previousFilingDate": "2024-11-14",
  "rows": [
    {
      "issuer": "Example Issuer",
      "cusip": "000000000",
      "status": "changed",
      "currentValueUsdThousands": 1200,
      "previousValueUsdThousands": 900,
      "deltaValueUsdThousands": 300,
      "currentShares": 10000,
      "previousShares": 8000,
      "deltaShares": 2000
    }
  ]
}
```

The route selects the latest two parsable reports. It does not accept arbitrary reporting periods. For a period-specific report, retrieve the underlying 13F filing first and retain both the filing date and the report date in your research record.

## Use cases

### Smart money tracking

Monitor how a selected manager's disclosed positions changed from one report to the next. Treat the result as a delayed disclosure signal, not a view of its current book.

### Crowded trade detection

Use the row-level diff to identify positions worth investigating, then compare the issuer's filings, valuation, and other managers separately.

### Portfolio rebalancing signals

Use disclosed changes as one input to a research process. Shares and reported value may move for reasons other than a discretionary buy or sell.

### Client reporting

Create a reviewed report that links each change to the relevant 13F source filing and explains the timing limitations to its reader.

## API endpoints

| Endpoint                      | Description                                                       |
| ----------------------------- | ----------------------------------------------------------------- |
| `POST /v1/owners/13f/compare` | Compare the latest two parsable reports for a manager CIK         |
| `GET /v1/owners/13f`          | Retrieve a normalized 13F report, with optional quarter selection |

## Why SEC API for 13F comparison

| What to check                   | Why it matters                                                                                    |
| ------------------------------- | ------------------------------------------------------------------------------------------------- |
| Filing date versus report date  | 13F data is delayed. The report date and the date the SEC received it answer different questions. |
| Added or removed versus changed | The response labels each position, but a changed row does not explain the manager's decision.     |
| Shares versus reported value    | Reported value is not a live market value and can change independently of share count.            |
| Source filing                   | A comparison is a navigation aid. Review the source 13F before citing a position change.          |

## Get started

<Card title="Get your API key" icon="key" href="/getting-started">
  Start comparing institutional holdings in under 60 seconds. 150 free API calls (one-time).
</Card>

* [13F Institutional Holdings API](/seo/13f-data-api)
* [Insider Trading API](/seo/insider-trading-api)
* [API Reference](/api-reference)