Insider Buy Signals

Filing-verified U.S. insider open-market purchase signals, parsed straight from SEC EDGAR Form 4 filings. This repo is the MIT-licensed client library and worked examples for the TradeStar Insider API and MCP server.

• Website: https://www.tradestarinsider.com
• REST (OpenAPI 3.0.2): https://api.tradestarinsider.com/v1/openapi.json
• MCP server (Streamable HTTP, no auth): https://mcp.tradestarinsider.com/mcp
• Live status: https://status.tradestarinsider.com

What the data is

We read Form 4 filings from SEC EDGAR and keep only the open-market buys that carry information:

• Cluster buys — two or more insiders buying the same company inside a single window of seven calendar days or fewer.
• Large buys — purchases large relative to the insider's existing holdings.

Option exercises, 10b5-1 planned sales, and sub-threshold noise (below $50,000) are dropped. Every field we return — shares, price, dollar value, percent versus holdings — is parsed from a real filing and ships with a link to that filing on sec.gov. Records that can't be linked to a filing are dropped, never guessed. No scores, no unsourced numbers. We call this Rule 2.

What the data is not

It is not a prediction. We tested whether these two filters precede price moves over our own history and could not find a return edge distinguishable from base rate, so we do not claim one. This is a clean, filing-verified lookup and verification layer over public purchases — you decide what they mean. It is also not real-time: ingestion is a once-daily weekday cron, so new filings surface next business day, not live.

Coverage

• Insider Form 4 buys: 172 U.S. trading days, 2026-01-20 → 2026-09-23, no gaps in the window (market holidays such as Presidents' Day carry no filings and are not gaps). Read the live number any time at /v1/health.
• Completeness: we capture 93.70% of in-window open-market purchases (lower bound 87.28%); of the filings we skip, only 0.75% (95% CI 0.34–1.63%) turn out to be purchases we genuinely missed — the rest are sales, option exercises, amendments, and sub-$50k buys we exclude by design.

Install

pip install insider-signals        # or, from a clone:  pip install -e .

Zero runtime dependencies — the client uses only the Python standard library.

Quickstart (free, no key)

The free tier answers on the open discovery surface with no key and per-IP rate limiting:

from insider_signals import InsiderSignals

api = InsiderSignals()                         # public base URL, no key

print(api.health()["datasets"]["insider"])     # coverage days + date range

for s in api.today():                          # today's filing-verified buys
    print(s["ticker"], s["value_usd"], s["filing_url"])

for s in api.clusters():                       # cluster buys (2+ insiders, ≤7 days)
    print(s["ticker"], s["cluster_insiders"], s["cluster_notional"])

# Verify a specific claim against the filings we hold:
v = api.verify("ETRA", "ORBIMED ADVISORS LLC")
print(v["status"], v["count"])                 # -> confirmed 2

See examples/rest_api.py for a runnable version.

Free tier vs. keyed tier

Tier	Methods	Access
Free (no key)	health, today, clusters, verify, verify_13d, verify_8k, verify_13f	Open /public/v1, per-IP rate limited
Keyed (RapidAPI)	by_ticker, by_range, filing, fund_changes, federal_awards_recent, activist_stakes_recent	Metered, through RapidAPI

For the keyed tier, subscribe on RapidAPI and construct the client with your key:

api = InsiderSignals(base_url="https://<your-rapidapi-host>", rapidapi_key="...")
for s in api.by_ticker("GME"):
    print(s["insider"], s["shares"], s["price_per_share"], s["filing_url"])

Calling a keyed method without a key raises InsiderSignalsError with status == 403.

Worked examples — one real request and response per tool

Every response below is a real capture from the live public API (coverage as of 2026-09-23).

today — today's insider buys

GET https://api.tradestarinsider.com/public/v1/signals/today

{
  "api_version": "v1",
  "endpoint": "signals/today",
  "rule2_guarantee": "Every record traces to a parsed SEC filing field and carries its source filing_url. Records without a filing link are dropped upstream and never returned.",
  "count": 0,
  "params": { "date": "2026-09-24" },
  "signals": []
}

(An empty set is normal pre-market / on a non-trading day; it repopulates the moment new filings materialize.)

clusters — cluster buys (2+ insiders, one issuer, ≤7 days)

GET https://api.tradestarinsider.com/public/v1/signals/clusters

{
  "api_version": "v1",
  "endpoint": "signals/clusters",
  "count": 1596,
  "signals": [
    {
      "filed_date": "2026-07-22",
      "ticker": "CLBK",
      "issuer_name": "Columbia Financial, Inc./MD/",
      "insider": "Splaine Thomas Jr",
      "relationship": { "director": false, "officer": true, "officer_title": "EVP, CFO" },
      "code": "P",
      "shares": 50000.0, "price_per_share": 10.0, "value_usd": 500000.0,
      "cluster": true, "cluster_insiders": 16, "cluster_notional": 4760370.0,
      "accession": "0001339736-26-000014",
      "filing_url": "https://www.sec.gov/Archives/edgar/data/2115119/000133973626000014/0001339736-26-000014-index.htm"
    }
  ]
}

verify — confirm an insider open-market-purchase claim

GET https://api.tradestarinsider.com/public/v1/verify?ticker=ETRA&person=ORBIMED ADVISORS LLC

{
  "api_version": "v1",
  "endpoint": "verify",
  "coverage_start": "2026-01-20", "coverage_end": "2026-09-23",
  "coverage_note": "Checked SEC Form-4 open-market purchases (code P) collected 2026-01-20..2026-09-23. Absence here means not in this window — not absence at the SEC.",
  "status": "confirmed",
  "matched": ["ticker/issuer", "person"],
  "filings": [
    {
      "ticker": "ETRA", "issuer_name": "Electra Therapeutics, Inc.",
      "insider": "ORBIMED ADVISORS LLC",
      "code": "P", "shares": 1000000.0, "price_per_share": 15.0, "value_usd": 15000000.0,
      "filed_date": "2026-09-23", "accession": "0000947871-26-000880",
      "filing_url": "https://www.sec.gov/Archives/edgar/data/2088082/000094787126000880/0000947871-26-000880-index.htm"
    }
  ],
  "count": 2,
  "message": "Confirmed: 2 matching Form-4 open-market purchase filing(s)."
}

A claim with no matching filing returns "status": "not_found" (in-window) or "out_of_coverage" (outside the collected days) — never a guess.

verify_13d — confirm a Schedule 13D activist-stake claim

GET https://api.tradestarinsider.com/public/v1/verify/13d?subject_name=New Fortress Energy Inc.&filer_name=Strategic Value Partners, LLC

{
  "endpoint": "verify/13d",
  "coverage_start": "2026-06-22", "coverage_end": "2026-09-18",
  "status": "confirmed",
  "filings": [
    {
      "filed_date": "2026-09-18", "form_type": "SCHEDULE 13D",
      "subject_name": "New Fortress Energy Inc.", "subject_tickers": ["NFE", "NFEGP"],
      "filer_name": "Strategic Value Partners, LLC",
      "percent_of_class": 14.7, "aggregate_amount_owned": 19208710.0,
      "signal": "new_13d_bare", "stated_intent": "New 13D. No activist purpose stated.",
      "accession": "0001193125-26-395888",
      "filing_url": "https://www.sec.gov/Archives/edgar/data/1749723/0001193125-26-395888.txt"
    }
  ],
  "count": 1,
  "message": "Confirmed: 1 matching Schedule 13D/13D-A filing(s)."
}

verify_8k — confirm an 8-K material-event claim

GET https://api.tradestarinsider.com/public/v1/verify/8k?cik=1650648&company_name=4D Molecular Therapeutics, Inc.

{
  "endpoint": "verify/8k",
  "coverage_start": "2025-03-06", "coverage_end": "2026-09-22",
  "status": "confirmed",
  "filings": [
    {
      "cik": "1650648", "company_name": "4D Molecular Therapeutics, Inc.",
      "accession": "0001193125-26-277563",
      "filing_date": "2026-06-22", "event_date": "2026-06-17", "form": "8-K",
      "items": [{ "code": "5.07", "label": "Submission of Matters to a Vote of Security Holders" }],
      "filing_url": "https://www.sec.gov/Archives/edgar/data/1650648/000119312526277563/"
    }
  ],
  "count": 4,
  "message": "Confirmed: 4 matching 8-K filing(s) carrying the claimed item(s)."
}

verify_13f — confirm a 13F institutional-holding claim

GET https://api.tradestarinsider.com/public/v1/verify/13f?filer=BERKSHIRE HATHAWAY INC&issuer_name=ALPHABET INC&quarter=2026-06-30

{
  "endpoint": "verify/13f",
  "coverage_start": "2024-06-30", "coverage_end": "2026-06-30",
  "coverage_note": "Values are AS-OF quarter-end and up to ~45 days stale.",
  "status": "held",
  "filings": [
    {
      "filer_name": "BERKSHIRE HATHAWAY INC",
      "as_of_quarter_end": "2026-06-30", "filed_date": "2026-08-14", "lag_days": 45,
      "change": "added", "issuer_name": "ALPHABET INC", "title_of_class": "CAP STK CL A",
      "value_usd": 28157599351, "prior_value_usd": 15600071913, "ssh_prnamt": 78791167,
      "accession": "0001193125-26-352200",
      "filing_url": "https://www.sec.gov/Archives/edgar/data/1067983/000119312526352200/"
    }
  ],
  "count": 2,
  "message": "Held: 2 matching 13F position(s) reported as of the covered quarter."
}

Response shape

Every data route returns the same envelope; the rows live under signals, and the client's list-returning methods hand you that list directly. The verify* methods return the full envelope (you want the status and matched/filings fields).

MCP server (for AI assistants)

Ask an AI client (Claude and other MCP clients) for these signals directly. Open, free, per-IP rate limited — no API key, no OAuth:

claude mcp add --transport http insider-signals https://mcp.tradestarinsider.com/mcp

Then ask: "Show today's insider buy signals" or "Any insider cluster buys this week? Link the filings." See examples/mcp_client.md for the tool list and a programmatic SDK example.

Pricing

Plan	Price	Requests
Basic	$0	3,000 / month
Pro	$18 / month	10,000 / month
Ultra	$58 / month	100,000 / month
Mega	$100 / month	500,000 / month

Hard limits, no overage — requests over the cap return 429 until the window resets. The free discovery surface and the MCP server are open and per-IP rate limited; metered API billing runs through RapidAPI.

Disclaimer

Information, not investment advice. Every figure is parsed from a public SEC filing and links to its source on sec.gov. Insider buying guarantees nothing — insiders are wrong plenty — but open-market purchases are real money on the line.

License

MIT. Changelog: CHANGELOG.md.