Nicholas Rempel

Posted on Dec 14

How to Build a Real-Time SEC Filing Monitor in Python (Under 50 Lines)

#api #python #tutorial #fintech

Ever wonder how hedge funds know about insider trades before you do?

They're not psychic. They just have systems monitoring SEC filings in real-time. The moment a Form 4 hits EDGAR, they know.

Today, we're building that system. In Python. In under 50 lines.

Why Monitor SEC Filings?

Three filings move markets:

8-K: Unscheduled material events (CEO quits, merger announced, lawsuit filed)
10-K/10-Q: Annual and quarterly financials
Form 4: Insider trading — when executives buy or sell their own stock

That last one is interesting. When a CEO buys $2M of their own company's stock, that's a signal. They know something.

What We're Building

A Python script that:

Checks for new filings every 5 minutes
Filters by your watchlist (specific tickers)
Prints alerts to console (easily extendable to Slack, email, etc.)

No scraping. No parsing HTML. No dealing with EDGAR's... quirks.

First, grab a free API key.

The Code

import requests
import time
from datetime import datetime

# Config
API_KEY = "your_api_key"  # Free tier at earningsfeed.com
BASE_URL = "https://earningsfeed.com/api/v1"
WATCHLIST = ["AAPL", "TSLA", "NVDA", "MSFT", "GOOGL"]
CHECK_INTERVAL = 300  # 5 minutes

# Track what we've already seen
seen_filings = set()

def get_recent_filings():
    """Fetch recent SEC filings for watchlist tickers."""
    headers = {"Authorization": f"Bearer {API_KEY}"}
    filings = []

    for ticker in WATCHLIST:
        response = requests.get(
            f"{BASE_URL}/filings",
            headers=headers,
            params={"ticker": ticker, "limit": 10}
        )
        if response.ok:
            filings.extend(response.json().get("items", []))

    return filings

def check_for_new_filings():
    """Check for new filings and alert on any we haven't seen."""
    filings = get_recent_filings()

    for filing in filings:
        filing_id = filing.get("accessionNumber")

        if filing_id and filing_id not in seen_filings:
            seen_filings.add(filing_id)
            alert(filing)

def alert(filing):
    """Print alert for new filing. Swap this for Slack/email/SMS."""
    company = filing.get("companyName", "Unknown")
    form_type = filing.get("formType", "???")
    filed_at = filing.get("filedAt", "")
    url = filing.get("url", "")

    print(f"""
🚨 NEW FILING DETECTED
━━━━━━━━━━━━━━━━━━━━━
Company:   {company}
Form:      {form_type}
Filed:     {filed_at}
Link:      {url}
━━━━━━━━━━━━━━━━━━━━━
    """)

def main():
    print(f"👀 Monitoring {len(WATCHLIST)} tickers: {', '.join(WATCHLIST)}")
    print(f"⏱️  Checking every {CHECK_INTERVAL // 60} minutes")
    print("Press Ctrl+C to stop\n")

    # Initial check
    check_for_new_filings()

    while True:
        time.sleep(CHECK_INTERVAL)
        print(f"[{datetime.now().strftime('%H:%M:%S')}] Checking...")
        check_for_new_filings()

if __name__ == "__main__":
    main()

That's it. Under 50 lines.

Running It

pip install requests
python sec_monitor.py

Output:

👀 Monitoring 5 tickers: AAPL, TSLA, NVDA, MSFT, GOOGL
⏱️  Checking every 5 minutes
Press Ctrl+C to stop

🚨 NEW FILING DETECTED
━━━━━━━━━━━━━━━━━━━━━
Company:   NVIDIA Corp
Form:      4
Filed:     2024-12-14T16:32:00.000Z
Link:      https://www.sec.gov/Archives/edgar/data/1045810/...
━━━━━━━━━━━━━━━━━━━━━

Make It Actually Useful

The alert() function is where you customize. Some ideas:

Slack notifications:

def alert(filing):
    requests.post(SLACK_WEBHOOK, json={
        "text": f"🚨 {filing['companyName']} just filed a {filing['formType']}"
    })

Filter by form type (only insider trades):

if filing.get("formType") == "4":
    alert(filing)

Only material events:

# In get_recent_filings(), add forms filter
params={"ticker": ticker, "forms": "8-K,4", "limit": 10}

Why I Built This

Full disclosure: I built Earnings Feed because I got tired of the alternatives.

EDGAR's direct API has rate limits that'll get you blocked. Most commercial APIs charge hundreds per month. I wanted something with a free tier that just... works.

The database covers every public company filing with the SEC. Every 10-K, every Form 4, every 8-K.

If you're building something in the fintech space, it might save you some headaches.

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