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

Python SDK

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

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

Python (requests)

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")

C++

#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;
}

Rust

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(())
}

JavaScript

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

Related

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