Corporate Lobbying API

Retrieve corporate lobbying filings from US Senate LDA (Lobbying Disclosure Act) disclosures. Track which firms lobby on behalf of a company, how much they spend, and which policy areas and government entities they target.

Endpoint

GET /v2/lobbying/{symbol}

Authentication

The API supports multiple authentication methods:

Method	Example
Bearer token (recommended)	`Authorization: Bearer YOUR_API_KEY`
X-API-Key header	`X-API-Key: YOUR_API_KEY`
Query parameter	`?apiKey=YOUR_API_KEY`
Legacy query parameter	`?token=YOUR_API_KEY`

Parameters

Path Parameters

Parameter	Type	Required	Description
`symbol`	string	Yes	Stock ticker symbol (e.g., `AAPL`, `MSFT`)

Query Parameters

Parameter	Type	Required	Description
`startDate`	string	No	Start date (YYYY-MM-DD)
`endDate`	string	No	End date (YYYY-MM-DD)
`limit`	integer	No	Maximum number of results to return (1-500)

Request

from finbrain import FinBrainClient

fb = FinBrainClient(api_key="YOUR_API_KEY")

df = fb.corporate_lobbying.ticker("AAPL",
                                   date_from="2025-01-01",
                                   date_to="2025-12-31",
                                   as_dataframe=True)
print(df)

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.finbrain.tech/v2/lobbying/AAPL"

import requests

headers = {"Authorization": "Bearer YOUR_API_KEY"}

response = requests.get(
    "https://api.finbrain.tech/v2/lobbying/AAPL",
    headers=headers,
    params={"limit": 10}
)
data = response.json()

for f in data["data"]["filings"]:
    print(f"{f['date']} {f['quarter']}: {f['registrantName']} "
          f"- ${f['income']:,.0f} income, ${f['expenses']:,.0f} expenses")

#include <iostream>
#include <string>
#include <curl/curl.h>
#include <nlohmann/json.hpp>

using json = nlohmann::json;

size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* userp) {
    userp->append((char*)contents, size * nmemb);
    return size * nmemb;
}

json get_corporate_lobbying(const std::string& symbol, const std::string& api_key) {
    CURL* curl = curl_easy_init();
    std::string response;

    if (curl) {
        std::string url = "https://api.finbrain.tech/v2/lobbying/" + symbol;

        struct curl_slist* headers = nullptr;
        std::string auth_header = "Authorization: Bearer " + api_key;
        headers = curl_slist_append(headers, auth_header.c_str());

        curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);
        curl_easy_perform(curl);
        curl_slist_free_all(headers);
        curl_easy_cleanup(curl);
    }

    return json::parse(response);
}

int main() {
    auto result = get_corporate_lobbying("AAPL", "YOUR_API_KEY");

    for (auto& f : result["data"]["filings"]) {
        std::cout << f["date"].get<std::string>() << " "
                  << f["quarter"].get<std::string>() << ": "
                  << f["registrantName"].get<std::string>()
                  << " - $" << f["income"].get<double>() << " income, $"
                  << f["expenses"].get<double>() << " expenses"
                  << std::endl;
    }

    return 0;
}

use reqwest::blocking::Client;
use serde::Deserialize;
use std::error::Error;

#[derive(Debug, Deserialize)]
struct Filing {
    date: String,
    #[serde(rename = "filingUuid")]
    filing_uuid: String,
    #[serde(rename = "filingYear")]
    filing_year: i32,
    quarter: String,
    #[serde(rename = "clientName")]
    client_name: String,
    #[serde(rename = "registrantName")]
    registrant_name: String,
    income: f64,
    expenses: f64,
    #[serde(rename = "issueCodes")]
    issue_codes: Vec<String>,
    #[serde(rename = "governmentEntities")]
    government_entities: Vec<String>,
}

#[derive(Debug, Deserialize)]
struct LobbyingData {
    symbol: String,
    name: String,
    filings: Vec<Filing>,
}

#[derive(Debug, Deserialize)]
struct LobbyingResponse {
    success: bool,
    data: LobbyingData,
}

fn get_corporate_lobbying(symbol: &str, api_key: &str)
    -> Result<LobbyingResponse, Box<dyn Error>> {
    let url = format!(
        "https://api.finbrain.tech/v2/lobbying/{}",
        symbol
    );

    let client = Client::new();
    let response: LobbyingResponse = client
        .get(&url)
        .bearer_auth(api_key)
        .send()?
        .json()?;

    Ok(response)
}

fn main() -> Result<(), Box<dyn Error>> {
    let result = get_corporate_lobbying("AAPL", "YOUR_API_KEY")?;

    for f in &result.data.filings {
        println!("{} {}: {} - ${} income, ${} expenses",
            f.date, f.quarter, f.registrant_name, f.income, f.expenses);
    }

    Ok(())
}

const response = await fetch(
  "https://api.finbrain.tech/v2/lobbying/AAPL",
  { headers: { "Authorization": "Bearer YOUR_API_KEY" } }
);
const result = await response.json();

for (const f of result.data.filings) {
  console.log(`${f.date} ${f.quarter}: ${f.registrantName} - $${f.income} income, $${f.expenses} expenses`);
}

Response

Success Response (200 OK)

{
  "success": true,
  "data": {
    "symbol": "AAPL",
    "name": "Apple Inc.",
    "filings": [
      {
        "date": "2025-09-15",
        "filingUuid": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
        "filingYear": 2025,
        "quarter": "Q3",
        "clientName": "Apple Inc.",
        "registrantName": "Fierce Government Relations",
        "income": 150000,
        "expenses": 0,
        "issueCodes": ["TAX", "TRD", "COM"],
        "governmentEntities": ["Senate", "House"]
      }
    ]
  },
  "meta": {
    "timestamp": "2026-03-12T12:00:00.000Z"
  }
}

Response Fields

Field	Type	Description
`success`	boolean	Whether the request was successful
`data.symbol`	string	Stock ticker symbol
`data.name`	string	Company name
`data.filings`	array	Array of lobbying filing objects
`meta.timestamp`	string	Response timestamp (ISO 8601)

Filing Object Fields

Field	Type	Description
`date`	string	Filing date (YYYY-MM-DD)
`filingUuid`	string	Unique filing identifier
`filingYear`	integer	Year of the filing
`quarter`	string	Filing quarter (Q1, Q2, Q3, Q4)
`clientName`	string	Company being represented
`registrantName`	string	Lobbying firm name
`income`	number	Income reported by the registrant (USD)
`expenses`	number	Expenses reported by the registrant (USD)
`issueCodes`	array	Policy area codes (e.g., TAX, TRD, COM)
`governmentEntities`	array	Government bodies engaged (e.g., Senate, House)

Errors

Code	Error	Description
400	Bad Request	Invalid symbol or parameters
401	Unauthorized	Invalid or missing API key
403	Forbidden	Authenticated, but not authorized to access this resource
404	Not Found	Ticker not found
429	Too Many Requests	Rate limit exceeded — wait and retry
500	Internal Server Error	Server-side error

Corporate Lobbying Dataset - Use cases and analysis examples
Stock Screener API - Screen lobbying data across tickers
Insider Transactions - Insider trading data
Congressional Trading - Congressional trading data