Form4API REST API Reference — SEC Form 4, 144 & 13F-HR Data

// introduction

Introduction

Form4API provides real-time SEC Form 4 insider trading data via a simple REST API. Every time a corporate insider — director, officer, or 10% owner — buys or sells shares, they must file Form 4 with the SEC within two business days. Form4API parses those filings continuously and surfaces the data through clean, developer-friendly endpoints. See the insider trading API overview for a high-level walkthrough of the endpoints and pricing.

https://api.form4api.com

A machine-readable OpenAPI 3.x specification is published at api.form4api.com/openapi/v1.json. Use it with Postman, openapi-generator-cli, or any OpenAPI-aware tool to scaffold a client in your language of choice. The spec stays in sync with the live API automatically.

// quickstart

Quickstart

Get your first API response in under two minutes.

npm install form4api

curl "https://api.form4api.com/v1/transactions?per_page=5" \
  -H "X-Api-Key: YOUR_API_KEY"

curl "https://api.form4api.com/v1/transactions?ticker=AAPL&code=P&per_page=10" \
  -H "X-Api-Key: YOUR_API_KEY"

# Page 1
curl "https://api.form4api.com/v1/transactions?ticker=NVDA&per_page=100&page=1" \
  -H "X-Api-Key: YOUR_API_KEY"

# Page 2 (repeat until response array is shorter than per_page)
curl "https://api.form4api.com/v1/transactions?ticker=NVDA&per_page=100&page=2" \
  -H "X-Api-Key: YOUR_API_KEY"

import asyncio
from form4api import AsyncForm4ApiClient

async def main():
    async with AsyncForm4ApiClient("YOUR_API_KEY") as client:
        txns = await client.transactions.list(ticker="AAPL", per_page=5)
        for t in txns:
            print(t.insider_name, t.shares_amount, "@", t.price_per_share)

asyncio.run(main())

// authentication

Authentication

All API requests must include your API key in the X-Api-Key request header. You can find your key in the dashboard.

Keep your API key secret — do not expose it in client-side JavaScript or commit it to source control. Use environment variables or a secrets manager. Form4API is built by Theodor Nielsen on 100% public SEC EDGAR data.

curl "https://api.form4api.com/v1/transactions" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "error": {
    "code": "MISSING_API_KEY",
    "message": "Missing or invalid X-Api-Key header.",
    "requestId": "req_abc123"
  }
}

// rate-limits

Rate Limits

Each API key has two independent limits: a per-minute burst and a daily cap. Both return 429 Too Many Requests with a Retry-After header (seconds) when exceeded.

Every response also carries the per-minute window state so you can throttle proactively instead of waiting for a 429: X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset (Unix timestamp, seconds, when the minute window resets).

Per-minute limit exceeded (resets in seconds)

{
  "error": {
    "code": "RATE_LIMIT_EXCEEDED",
    "message": "Rate limit exceeded. Resets in 47 seconds.",
    "requestId": "0HN9K2P4QR8S1:00000001"
  }
}

Daily cap exceeded (resets at midnight UTC)

{
  "error": {
    "code": "DAILY_LIMIT_EXCEEDED",
    "message": "Daily request limit reached. Resets at midnight UTC.",
    "requestId": "0HN9K2P4QR8S1:00000002"
  }
}

// pagination & conventions

Pagination & conventions

Every list endpoint follows the same pagination contract — predictable across /v1/transactions, /v1/filings, /v1/insiders, /v1/companies, /v1/signals, /v1/form144, /v1/holdings, and /v1/managers. Each endpoint page references this section instead of re-stating the rules.

Query parameters

How do I know when I've reached the end?

Every list endpoint returns a JSON array. When a page returns fewer records than per_page, you've reached the end. There's no total-count header, no next cursor token, and no has_more field — the short-page signal is the contract. This keeps responses cacheable at the CDN edge (every query is just a deterministic URL) and avoids the consistency problems of cursor pagination over an actively-updated dataset.

Built-in paginate helper

Both SDKs expose a paginate() method that handles the loop for you — yields one page (an array) at a time, retries on 429, stops on the first short page. Prefer it over hand-written loops.

# Page through all NVDA insider transactions, 100 per page
curl "https://api.form4api.com/v1/transactions?ticker=NVDA&per_page=100&page=1" \
  -H "X-Api-Key: YOUR_API_KEY"

curl "https://api.form4api.com/v1/transactions?ticker=NVDA&per_page=100&page=2" \
  -H "X-Api-Key: YOUR_API_KEY"

Other conventions

// errors

Errors

All errors use a consistent JSON envelope. The code field is a machine-readable string you can match on; the requestId can be sent to support to help diagnose issues.

{
  "error": {
    "code": "INVALID_API_KEY",
    "message": "The provided API key is invalid.",
    "requestId": "req_7f3a9c"
  }
}

// transactions

Transactions

Returns individual insider transactions parsed from Form 4 filings. Each record represents a single row in a Form 4 table — one trade by one insider at one price.

Date filters (from / to) are both inclusive, treated as UTC, and filter on transactionDate. A date-only value (e.g. 2026-01-01) is interpreted as 2026-01-01T00:00:00Z. Results are ordered by transactionDate descending.

curl "https://api.form4api.com/v1/transactions?ticker=AAPL&per_page=5" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "ticker": "AAPL",
    "companyName": "Apple Inc.",
    "insiderName": "Cook Timothy D",
    "insiderCik": "0001214156",
    "insiderTitle": "Chief Executive Officer",
    "isDirector": false,
    "isOfficer": true,
    "is10PctOwner": false,
    "accessionNumber": "0001140361-26-013190",
    "securityTitle": "Common Stock",
    "transactionCode": "S",
    "isOpenMarket": true,
    "is10b5Plan": false,
    "sharesAmount": 5087,
    "pricePerShare": 251.25,
    "totalValue": 1278153.75,
    "sharesOwnedAfter": 3340280,
    "directIndirect": "D",
    "isDerivative": false,
    "transactionDate": "2026-04-02T00:00:00Z",
    "periodOfReport": "2026-04-01T00:00:00Z",
    "return1d": 0.0124,
    "return1w": 0.0237,
    "return1m": 0.0418,
    "return3m": 0.1156,
    "return6m": 0.1842
  }
]

// filings

Filings

Returns Form 4 filing headers. Use these endpoints when you need filing-level metadata such as the accession number, filed timestamp, and period of report. To get the underlying transactions, use /v1/transactions.

curl "https://api.form4api.com/v1/filings/recent?per_page=10" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "accessionNumber": "0001140361-26-019658",
    "companyTicker": "GYRE",
    "companyName": "GYRE THERAPEUTICS, INC.",
    "periodOfReport": "2026-05-05T00:00:00Z",
    "filedAt": "2026-05-08T02:02:09Z",
    "amendmentType": "Original",
    "transactionCount": 2
  }
]

curl "https://api.form4api.com/v1/filings/0001209191-26-034821" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "accessionNumber": "0001140361-26-017175",
  "companyTicker": "AAPL",
  "companyName": "Apple Inc.",
  "periodOfReport": "2026-04-23T00:00:00Z",
  "filedAt": "2026-05-04T07:01:02Z",
  "amendmentType": "Original",
  "transactionCount": 1
}

// insiders

Insiders

Search for individual insiders (directors, officers, 10%+ owners) by name, fetch a single insider profile by CIK, or retrieve their complete trade history.

curl "https://api.form4api.com/v1/insiders?name=cook" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "cik": "0001214128",
    "name": "Cook Timothy D",
    "isDirector": true,
    "isOfficer": true,
    "isTenPercentOwner": false,
    "officerTitle": "Chief Executive Officer",
    "totalFilings": 48
  }
]

curl "https://api.form4api.com/v1/insiders/0001214128" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "cik": "0001214128",
  "name": "Cook Timothy D",
  "isDirector": true,
  "isOfficer": true,
  "isTenPercentOwner": false,
  "officerTitle": "Chief Executive Officer",
  "totalFilings": 48
}

curl "https://api.form4api.com/v1/insiders/0001214128/transactions?per_page=10" \
  -H "X-Api-Key: YOUR_API_KEY"

curl "https://api.form4api.com/v1/insiders/0001214128/summary" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "cik": "0001214128",
  "name": "Cook Timothy D",
  "officerTitle": "Chief Executive Officer",
  "isDirector": true,
  "isOfficer": true,
  "isTenPercentOwner": false,
  "career": {
    "firstTransaction": "2011-09-09T00:00:00Z",
    "lastTransaction": "2026-04-30T00:00:00Z",
    "totalTransactions": 142,
    "totalBoughtUsd": 0,
    "totalSoldUsd": 821345670.00,
    "netUsd": -821345670.00,
    "companies": [
      { "ticker": "AAPL", "companyName": "Apple Inc.", "transactionCount": 142, "firstAtCompany": "2011-09-09T00:00:00Z" }
    ],
    "transactionTypeBreakdown": {
      "P": 0, "S": 78, "F": 12, "M": 36, "A": 14, "G": 0, "Other": 2
    },
    "tenB5Plan": {
      "totalUnderPlan": 64,
      "totalDiscretionary": 14,
      "pctUnder10b5Plan": 45.07
    },
    "returns": {
      "openMarketTransactionsWithReturns": 78,
      "avgReturn1d": 0.0021,
      "avgReturn1w": 0.0114,
      "avgReturn1m": 0.0327,
      "avgReturn3m": 0.0865,
      "avgReturn6m": 0.1542
    }
  }
}

curl "https://api.form4api.com/v1/insiders/0001214128/scorecard" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "insiderCik": "0001214128",
  "insiderName": "Cook Timothy D",
  "scoredBuyCount": 12,
  "sampleSufficient": true,
  "hitRate3m": 0.75,
  "avgReturn3m": 0.112,
  "medianReturn3m": 0.084,
  "scoredBuyCount6m": 10,
  "sampleSufficient6m": true,
  "hitRate6m": 0.70,
  "avgReturn6m": 0.198,
  "medianReturn6m": 0.153,
  "bestBuy": {
    "ticker": "AAPL",
    "filedAt": "2019-08-14T00:00:00Z",
    "return3m": 0.412
  },
  "worstBuy": {
    "ticker": "AAPL",
    "filedAt": "2022-02-01T00:00:00Z",
    "return3m": -0.218
  },
  "lastTradeAt": "2024-11-01T00:00:00Z",
  "methodology": "absolute-return-v1"
}

curl "https://api.form4api.com/v1/insiders/leaderboard?per_page=10" \
  -H "X-Api-Key: YOUR_API_KEY"

// companies

Companies

Look up a company by ticker to get its SEC profile and the list of registered insiders who have filed Form 4 for that company.

curl "https://api.form4api.com/v1/companies?sort=totalFilings&limit=10" \
  -H "X-Api-Key: YOUR_API_KEY"

curl "https://api.form4api.com/v1/companies/AAPL" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "cik": "0000320193",
  "name": "Apple Inc.",
  "ticker": "AAPL",
  "exchange": "Nasdaq",
  "totalFilings": 119,
  "activeInsiders": 19,
  "sicDescription": "Electronic Computers",
  "stateOfIncorporation": "CA",
  "website": null
}

curl "https://api.form4api.com/v1/companies/AAPL/insiders" \
  -H "X-Api-Key: YOUR_API_KEY"

// signals

Signals

Signals surface statistically notable insider activity. A cluster buy is triggered when 3 or more distinct insiders at the same company file open-market purchases (code P) within a rolling 5-day window ending on the filing date. A cluster sell follows the same rule for sales (code S). Option exercises, grants, and tax withholdings do not count toward the cluster threshold. Pre-scheduled trades filed under a Rule 10b5-1 plan are also excluded — these carry no conviction signal.

One signal record is stored per company per day and is updated each time a new filing for that company is processed. Signals are ordered by signalDate descending.

curl "https://api.form4api.com/v1/signals?cluster_buy=true&per_page=5" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "ticker": "OPCH",
    "companyName": "Option Care Health, Inc.",
    "signalDate": "2026-05-07T00:00:00Z",
    "buySellRatio": 2.47,
    "isClusterBuy": true,
    "isClusterSell": false,
    "insiderCount": 11
  }
]

{
  "error": {
    "code": "PLAN_REQUIRED",
    "message": "This endpoint requires the Business plan or higher. Your current plan is Free.",
    "requestId": "req_7f3a9c"
  }
}

curl "https://api.form4api.com/v1/signals/sentiment/NVDA?months=6" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "ticker": "NVDA",
  "companyName": "NVIDIA Corporation",
  "monthly": [
    {
      "period": "2026-05",
      "score": -82.5,
      "buyValue": 250000.00,
      "sellValue": 2580000.00,
      "buyCount": 1,
      "sellCount": 4
    },
    {
      "period": "2026-04",
      "score": 12.7,
      "buyValue": 1100000.00,
      "sellValue": 850000.00,
      "buyCount": 3,
      "sellCount": 2
    }
  ]
}

// form-144

Form 144

Form 144 is the SEC notice of proposed sale — insiders must file it before selling restricted or control securities above the 5,000-share or $50,000 / 3-month threshold. The actual sale shows up later in Form 4, typically within a few days.

This makes Form 144 a leading indicator: you see the intent to sell before the trade prints. The isUnder10b5Plan flag separates pre-scheduled disposition (low signal) from discretionary intent (higher signal) — derived from the planAdoptionDates element in the filing.

Unlike Form 4, Form 144 carries the insider as plain text only — there is no CIK on the insider field. Use insider_name as a forgiving ILIKE substring (matches cook against Timothy D Cook or COOK, TIM).

curl "https://api.form4api.com/v1/form144?ticker=NVDA&exclude_10b5=true&per_page=5" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "accessionNumber": "0001950047-26-003316",
    "ticker": "NVDA",
    "companyName": "NVIDIA Corporation",
    "insiderName": "Huang Jen Hsun",
    "relationship": "Director / Officer",
    "broker": "Charles Schwab",
    "sharesProposed": 120000,
    "aggregateMarketValue": 24500000.00,
    "approxSaleDate": "2026-06-03",
    "exchange": "NASDAQ",
    "acquiredDate": "2019-12-12",
    "natureOfAcquisition": "Founders Shares",
    "isUnder10b5Plan": false,
    "filedAt": "2026-05-21T00:00:00Z",
    "noticeDate": "2026-05-21"
  }
]

{
  "error": {
    "code": "PLAN_REQUIRED",
    "message": "This endpoint requires the Business plan or higher. Your current plan is Free.",
    "requestId": "req_7f3a9c"
  }
}

// transactions-export

Transactions Export

Streams a bulk RFC 4180 CSV of Form 4 insider transactions. Accepts the same filter grammar as GET /v1/transactions but returns a CSV file rather than paginated JSON. Use this endpoint when you need a full dataset for backtesting, spreadsheet analysis, or bulk ingestion.

curl -H "X-Api-Key: YOUR_API_KEY" \
  "https://api.form4api.com/v1/transactions/export?ticker=AAPL&from=2020-01-01&to=2024-12-31" \
  -o aapl-insider.csv

filedAt,transactionDate,ticker,companyName,insiderName,insiderCik,insiderTitle,isDirector,isOfficer,isTenPercentOwner,transactionCode,isBuyOrSell,isDerivative,is10b5Plan,securityTitle,sharesAmount,pricePerShare,value,sharesOwnedAfter,directOrIndirect,accessionNumber,periodOfReport,return1d,return1w,return1m,return3m,return6m

{
  "error": {
    "code": "EXPORT_UNBOUNDED",
    "message": "At least one of ticker, cik, insider_cik, or from is required for export requests.",
    "requestId": "req_8c2b1d"
  }
}

// form-144-export

Form 144 Export

Streams a bulk RFC 4180 CSV of Form 144 notice-of-proposed-sale filings. Accepts the same filter grammar as GET /v1/form144 but returns a CSV file rather than paginated JSON. Use this endpoint to build offline datasets, backtest leading-indicator strategies, or track proposed-sale history across a watchlist.

curl -H "X-Api-Key: YOUR_API_KEY" \
  "https://api.form4api.com/v1/form144/export?ticker=NVDA&from=2020-01-01&to=2024-12-31" \
  -o nvda-form144.csv

filedAt,noticeDate,ticker,companyName,insiderName,relationship,brokerName,sharesProposed,aggregateMarketValue,approxSaleDate,exchange,acquiredDate,natureOfAcquisition,isUnder10b5Plan,accessionNumber

{
  "error": {
    "code": "EXPORT_UNBOUNDED",
    "message": "At least one of ticker, insider_name, or from is required for export requests.",
    "requestId": "req_9a3e4f"
  }
}

// holdings

Institutional Holdings (13F-HR)

Quarterly Form 13F-HR holdings filed by institutional investment managers with discretion over more than $100M in 13F-eligible equity securities. Filed within 45 days of quarter end (so Q1 holdings land mid-May, Q2 mid-August, etc.).

Each row is one position. A single security can appear multiple times in one filing when the manager attributes shares across sub-managers — Berkshire, for instance, lists each security up to 14 times, once per subsidiary insurance company.

Use cusip when you need exact security matching across all filers (the only stable cross-filing identifier). Use ticker for issuer-side queries — this resolves via the issuer CIK and only covers issuers we already track from Form 4, so coverage is high for US large-caps but partial for ETFs and bonds.

curl "https://api.form4api.com/v1/holdings?manager_cik=1067983&per_page=3" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "manager": "Berkshire Hathaway Inc",
    "managerCik": "1067983",
    "reportPeriod": "2026-03-31T00:00:00Z",
    "issuerName": "APPLE INC",
    "ticker": "AAPL",
    "cusip": "037833100",
    "titleOfClass": "COM",
    "value": 91234567890,
    "shares": 300000000,
    "shareType": "SH",
    "investmentDiscretion": "SOLE",
    "votingSole": 300000000,
    "votingShared": 0,
    "votingNone": 0,
    "accessionNumber": "0001193125-26-226661",
    "filedAt": "2026-05-15T00:00:00Z"
  }
]

curl "https://api.form4api.com/v1/managers?min_aum=100000000000&per_page=5" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "name": "Berkshire Hathaway Inc",
    "cik": "1067983",
    "latestReportPeriod": "2026-03-31T00:00:00Z",
    "latestAum": 263095703570,
    "latestPositionCount": 90,
    "latestFiledAt": "2026-05-15T00:00:00Z",
    "latestAccessionNumber": "0001193125-26-226661"
  }
]

{
  "error": {
    "code": "PLAN_REQUIRED",
    "message": "This endpoint requires the Business plan or higher. Your current plan is Free.",
    "requestId": "req_7f3a9c"
  }
}

// webhooks

Webhooks

Subscribe to real-time events instead of polling. When a matching event fires, Form4API POSTs a JSON payload to your endpoint within seconds of the SEC publishing the filing. Each delivery is signed with X-Insider-Signature so you can verify it came from us.

curl -X POST "https://api.form4api.com/v1/webhooks" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://yourapp.com/webhooks/form4",
    "eventTypes": ["TransactionFiled", "ClusterBuy"]
  }'

curl "https://api.form4api.com/v1/webhooks" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "subscriptionId": 42,
    "url": "https://yourapp.com/webhooks/form4",
    "eventTypes": ["TransactionFiled", "ClusterBuy"],
    "createdAt": "2026-05-01T10:00:00Z",
    "isActive": true
  }
]

curl -X DELETE "https://api.form4api.com/v1/webhooks/42" \
  -H "X-Api-Key: YOUR_API_KEY"

# Returns 204 No Content on success

curl "https://api.form4api.com/v1/webhooks/events" \
  -H "X-Api-Key: YOUR_API_KEY"

# Replay from a specific point in time (up to 30 days back)
curl "https://api.form4api.com/v1/webhooks/events?since=2026-05-01T00:00:00Z" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "deliveryId": 1042,
    "subscriptionId": 7,
    "eventType": "TransactionFiled",
    "attemptCount": 1,
    "deliveredAt": "2026-05-04T14:23:11Z",
    "nextRetryAt": null,
    "lastStatusCode": 200,
    "isDead": false,
    "payload": { "filingId": 123, "accessionNumber": "0001140361-26-017175" }
  }
]

{
  "type": "TransactionFiled",
  "data": {
    "ticker": "AAPL",
    "companyName": "Apple Inc.",
    "insiderName": "Cook Timothy D",
    "insiderTitle": "Chief Executive Officer",
    "isDirector": false,
    "isOfficer": true,
    "is10PctOwner": false,
    "transactionCode": "S",
    "isOpenMarket": true,
    "is10b5Plan": false,
    "sharesAmount": 10000,
    "pricePerShare": 212.45,
    "totalValue": 2124500.00,
    "transactionDate": "2026-04-30T00:00:00Z"
  }
}

import crypto from 'crypto'

export async function POST(req: Request) {
  const body = await req.text()
  const sig = req.headers.get('X-Insider-Signature') ?? ''
  const expected = 'sha256=' + crypto
    .createHmac('sha256', process.env.WEBHOOK_SECRET!)
    .update(body)
    .digest('hex')

  if (sig !== expected) {
    return new Response('Invalid signature', { status: 401 })
  }

  const event = JSON.parse(body)
  // handle event.type: 'TransactionFiled' | 'ClusterBuy' | 'ClusterSell'
  return new Response('ok', { status: 200 })
}

// usage

Usage

Check your current quota, view daily request history, and inspect recent API calls — all from your own API key without needing to log into the dashboard.

curl "https://api.form4api.com/v1/keys/usage" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "plan": "Free",
  "requestsToday": 42,
  "dailyLimit": 500,
  "requestsThisMonth": 842,
  "resetAt": "2026-05-16T00:00:00Z"
}

curl "https://api.form4api.com/v1/keys/usage/history?days=7" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  { "date": "2026-05-15", "count": 42 },
  { "date": "2026-05-14", "count": 318 },
  { "date": "2026-05-13", "count": 204 }
]

curl "https://api.form4api.com/v1/keys/usage/activity?limit=5" \
  -H "X-Api-Key: YOUR_API_KEY"

[
  {
    "endpoint": "/v1/transactions",
    "statusCode": 200,
    "durationMs": 4,
    "createdAt": "2026-05-15T07:31:22Z"
  },
  {
    "endpoint": "/v1/companies/AAPL",
    "statusCode": 200,
    "durationMs": 3,
    "createdAt": "2026-05-15T07:31:18Z"
  }
]

// billing

Billing

Programmatically generate a Stripe checkout URL to upgrade your plan. The endpoint requires a valid API key and returns a one-time checkout session URL. Redirect the user to this URL to complete payment. See pricing for plan limits and prices.

curl -X POST "https://api.form4api.com/v1/billing/checkout?plan=Pro" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "checkoutUrl": "https://checkout.stripe.com/c/pay/cs_live_..."
}

curl -X POST "https://api.form4api.com/v1/billing/portal" \
  -H "X-Api-Key: YOUR_API_KEY"

{
  "portalUrl": "https://billing.stripe.com/session/..."
}

// mcp

MCP / AI Assistants

The form4api-mcp package wraps the Form4API REST API as an MCP (Model Context Protocol) server. Once configured, any MCP-compatible AI assistant — Claude Desktop, Claude Code, Cursor, Windsurf, Zed — can call Form4API directly without you writing any code.

# Claude Desktop — claude_desktop_config.json
# macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
# Windows: %APPDATA%\Claude\claude_desktop_config.json
{
  "mcpServers": {
    "form4api": {
      "command": "npx",
      "args": ["-y", "form4api-mcp"],
      "env": {
        "FORM4API_KEY": "fapi_live_your_key_here"
      }
    }
  }
}

// faq

Frequently asked questions

Developer-focused answers covering amendments, 10b5-1 plan filtering, date semantics, post-trade returns, rate-limit behaviour, and sandbox availability. The same content emits an identical FAQPage JSON-LD block on this page.

// glossary

Glossary

Key terms from SEC filings and insider trading data used throughout this API. Mirrored as a DefinedTermSet JSON-LD block on this page so AI crawlers can quote each definition cleanly.

Accession Number

The SEC's unique identifier for a single filing, formatted as XXXXXXXXXX-YY-ZZZZZZ (e.g. 0001140361-26-013190). The first segment is the filer's CIK, YY is the year, and ZZZZZZ is a sequence number. Use this to fetch a specific filing from the /v1/filings/{accession} endpoint.

Beneficial Ownership

Shares that an insider has an economic interest in, even if they are not registered in the insider's name. An insider is considered a beneficial owner of shares held by a spouse, a trust they control, or a company they own more than 50% of.

CIK

Central Index Key — the SEC's permanent numeric identifier for every entity that files with the SEC, including individuals and companies. CIKs are always 10 digits, zero-padded (e.g. 0001214156). Use a CIK to look up an insider's full filing history via /v1/insiders/{cik}.

Open Market Transaction

A discretionary purchase or sale executed on a public exchange at the prevailing market price. In Form 4 data, open-market transactions are identified by transaction codes P (purchase) and S (sale). These are the trades most relevant for signal analysis — they represent the insider choosing to put their own money in, or taking it out. Non-market events such as option exercises (M), tax withholding (F), grants (A), and gifts (G) are also reported on Form 4 but are not discretionary and should not be treated as conviction signals. The isOpenMarket field makes this distinction explicit.

Rule 10b5-1 Plan

A pre-scheduled trading arrangement that allows corporate insiders to buy or sell company stock at predetermined times, prices, or quantities, set up in advance when the insider held no material non-public information (MNPI). Trades executed under a 10b5-1 plan are automatic — the insider does not make a real-time decision to trade. Because they are pre-committed and not driven by current information, they carry no conviction signal. Form4API marks these trades with is10b5Plan: true and excludes them from cluster buy/sell signal computation. Use ?exclude_10b5=true on the transactions endpoint to filter them out.

Cluster Signal

A ClusterBuy or ClusterSell signal is triggered when three or more insiders at the same company independently file Form 4 transactions in the same direction (all buys or all sells) within a 5-day window. Clusters are considered a stronger signal than a single insider trade because they suggest shared conviction among multiple informed parties.

Derivative Security

A security whose value is derived from an underlying asset — typically company stock. Common derivatives reported on Form 4 include stock options, warrants, and convertible notes. When isDerivative is true in a transaction, sharesAmount refers to the number of shares underlying the derivative, not shares directly transferred.

Direct vs Indirect Ownership

The directIndirect field indicates how an insider holds shares. "D" (direct) means shares are registered in the insider's own name. "I" (indirect) means shares are held through an intermediary such as a trust, LLC, partnership, or a family member's account.

Form 4

The SEC filing required under Section 16 of the Securities Exchange Act of 1934. Corporate insiders — directors, officers, and shareholders owning more than 10% of a company — must file Form 4 within two business days of any change in their beneficial ownership of company securities. Form4API parses every Form 4 filed with the SEC and exposes the data via this API.

Insider

For SEC reporting purposes, an insider is any director, officer, or 10%-or-greater shareholder of a public company. These individuals have a heightened duty to disclose their trades because they may have access to material non-public information. Insider trading data is public — only the trades of these registered insiders are reported on Form 4.

Period of Report

The date field on a Form 4 indicating when the reported transaction occurred. This is usually identical to transactionDate but can differ for transactions that are grouped or reported after a delay. When the two dates differ, periodOfReport reflects the filing's stated coverage date.

Section 16

Section 16 of the Securities Exchange Act requires insiders to report their ownership and any changes to it. Section 16(a) mandates the Form 4 filings this API is built on. Section 16(b) requires insiders to disgorge any "short-swing profits" — gains from buying and selling the same stock within a six-month window.

Transaction Code

A single letter on Form 4 indicating the nature of the transaction. The most common codes are: P (open-market purchase), S (open-market sale), A (grant or award), M (exercise or conversion of derivative), F (shares withheld to cover tax on vest/exercise), D (disposition to the issuer). Less common but valid codes include: C (conversion of derivative), J (other acquisition or disposition), G (gift), X (in-the-money derivative exercise), O (out-of-the-money derivative exercise), E (expiration of long derivative), H (expiration of short derivative), I (discretionary transaction), L (small acquisition), U (tender offer disposition), W (acquisition by will or descent), Z (voting trust deposit/withdrawal), V (voluntary exempted disposition), K (equity swap), B (automatic sell to cover taxes), T (Rule 10b5-1 plan transaction).