SEC Schedule 13D API

Schedule 13D API (Activist Stakes)

Catch activist positions as they form. The Schedule 13D API surfaces beneficial-ownership reports filed when an investor crosses 5% with intent to influence.

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JSON responsesOpenAPI documentedcURL / Python / JS / GoFree tier available

What is Schedule 13D?

Schedule 13D is filed by any person or group acquiring beneficial ownership of more than 5% of a company’s voting stock with the intent to influence control — the classic activist filing.

It discloses the stake size, purpose, and plans, making it a leading indicator of activist campaigns, takeover interest, and proxy fights.

The Finsider Schedule 13D API indexes these filings so you can detect new 5%+ positions and monitor activist activity.

Fetch Schedule 13D filings

List recent Schedule 13D filings, filterable by company, ticker, and date.

cURLPythonJavaScriptGo

curl -s "https://api.secapi.dev/v1/filings?formTypes=SC%2013D&limit=20" \
  -H "x-api-key: $SECAPI_KEY"

import requests

resp = requests.get(
    "https://api.secapi.dev/v1/filings?formTypes=SC%2013D&limit=20",
    headers={"x-api-key": "YOUR_API_KEY"},
    timeout=30,
)
resp.raise_for_status()
data = resp.json()
print(data)

const res = await fetch("https://api.secapi.dev/v1/filings?formTypes=SC%2013D&limit=20", {
  method: "GET",
  headers: { "x-api-key": process.env.SECAPI_KEY },
});
if (!res.ok) throw new Error(`HTTP ${res.status}`);
const data = await res.json();
console.log(data);

package main

import (
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
)

func main() {
	req, _ := http.NewRequest("GET", "https://api.secapi.dev/v1/filings?formTypes=SC%2013D&limit=20", nil)
	req.Header.Set("x-api-key", os.Getenv("SECAPI_KEY"))

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	defer resp.Body.Close()

	body, _ := io.ReadAll(resp.Body)
	fmt.Println(string(body))
}

Who files Schedule 13D?

Filer	Requirement
Activist investors	Crossing 5% with intent to influence
Acquirers	Building a position toward control
Groups	Parties acting together (a "group")
Deadline	Within days of crossing the threshold

Deadlines & coverage

Aspect	Detail
Trigger	Acquiring >5% with intent to influence
Amendments	SC 13D/A on material changes
Contrast	Passive investors file Schedule 13G
Availability	Indexed within minutes of acceptance

Key data fields

A sample of the structured fields returned for Schedule 13D data.

Field	Description
`companyName` / `cik`	Subject company
`formType`	`SC 13D` / `SC 13D/A`
`filingDate`	Date the stake was disclosed
`documents`	Filing content and exhibits
`accessionNumber`	Unique SEC identifier

Related API endpoints

Deep-link into the interactive reference to try these live.

GET /v1/filings List filings Search and page every SEC filing, filtered by form type, company, ticker, and date. GET /v1/filings/{cik}/{accessionNumber}/documents List filing documents and exhibits Enumerate every document and exhibit attached to a filing, with direct URLs. GET /v1/entities/{identifier}/filings List a company’s filings Return every filing for a company by ticker or CIK.

Frequently asked questions

What is the Schedule 13D API?

An endpoint that returns SEC Schedule 13D beneficial-ownership reports — the activist filings made when an investor crosses 5% with intent to influence — as structured JSON.

What is the difference between 13D and 13G?

Schedule 13D is filed by investors who intend to influence control (often activists); Schedule 13G is the short-form report for passive investors.

Build with the Schedule 13D API

Create a free account, grab an API key, and make your first request in under a minute.

Get your API key Browse the API reference