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Regulatory market data, traced to the filing

13F holdings, insider trades and congressional disclosures, normalized from the source. Browse them in the Terminal, query them over REST, or let your AI agent fetch them over MCP.

Get API key Open the Terminal
Works with

SEC Form 13F-HR · Berkshire Hathaway Inc

Institutional holdings

See 12,900+ institutions

Every long U.S. equity position reported on Form 13F, with share counts, reported value, portfolio weight and quarter change.

QuarterlyCUSIP → ticker
MCP
get_institution_holdings
REST
GET /api/v1/holdings/1067983

  • 23

    datasets

  • 100M+

    source-traced rows

  • 12,900+

    13F institutions

  • 44

    REST endpoints

  • 24

    MCP tools for agents

Collected directly from SEC EDGAR, the U.S. House and Senate, FINRA, the Federal Reserve and the U.S. Treasury.

Works with your AI agent

Connect Claude, Cursor, Codex or any MCP client in one line. Ask in plain English; the answer cites the filing.

ExampleAn MCP client connected to ko.io

How many Apple shares did Berkshire Hathaway hold at the end of Q2 2026, and how big is the position?

Calledget_institution_holdings{ institution: "Berkshire Hathaway", limit: 3 }

Berkshire Hathaway reported 227.92 million Apple shares for the quarter ending June 30, 2026, worth $65.95 billion. At 22.04% of the reported portfolio it is Berkshire's largest position, ahead of American Express at 17.14%. The share count is unchanged from the prior quarter.

Source: 13F‑HR, period 2026-06-30, SEC EDGAR (opens the filing on sec.gov)

Connect in one line

Pick your client, copy, done. Works without a key in demo mode.

Claude Code: run in your terminal.

claude mcp add ko-sec-data --transport http https://mcp.ko.io/mcp
24 tools, 19 on the free tierAll tools and setup

Securities regulatory data, one key

View all 23 datasets

13F holdings

Quarterly positions for 12,900+ institutions, one row per issuer, with quarter-over-quarter change.

QuarterlySEC EDGAR

Insider trades

Form 4 transactions by officers and directors, open-market buys and sells separated from awards.

DailyForm 4Form 144

Congress trades

House and Senate periodic transaction reports, with the disclosed range and the reporting delay.

DailyHouse ClerkSenate

Fails-to-deliver & Reg SHO

SEC fails-to-deliver and the Reg SHO threshold lists, joined to the same ticker and CUSIP keys.

Twice monthlySECReg SHO

Macro

Treasury yields, Fed rates, financial stress and economic indicators, on the same API as the filings.

DailyTreasuryFederal Reserve
8-K eventsForm 14413D / 13GN-PORTForm DDEF 14AReg SHO thresholdFinancialsCrypto ETF holdersTreasury auctionsCFTCFDIC+ more

18 more datasets

Material events, ownership thresholds, fund holdings, filer profiles and more, keyed to the same issuers.

Browse the catalog

Terminal

Browse every dataset in one workbench. Select any row to inspect its source filing.

WebCSV export

REST API

JSON over HTTPS, paginated, one key for every dataset.

API44 endpoints

MCP server

24 tools that let Claude, Cursor, Codex and other MCP clients query the filings.

MCPStreamable HTTP

Source trace

Every row names the form, period and filer it came from, and pages link to the filer's filings on SEC EDGAR.

SECHouseSenate

Every dataset in one workbench

The Terminal puts the filings in one table: pick a dataset, narrow the rows, and open any record to see where it came from.

Open the Terminal
ko.io/terminal
ko.io Terminal: Institutions dataset with State Street Corp selected and its 13F filer inspector openko.io Terminal: Institutions dataset with State Street Corp selected and its 13F filer inspector open

  1. Pick a dataset

    Institutions, stocks, insider and congress trades, crypto ETF holders.

  2. Narrow the rows

    Filter by category, search managers, sort by any column.

  3. Select a row

    Keyboard first: arrows to move, enter to inspect, esc to close.

  4. See the source

    The inspector shows the filer, its largest positions and the form it came from.

One position, one row, in one request

Berkshire's 13F-HR lists Apple across 12 rows, split by manager and discretion. ko.io consolidates them into the single position an analyst actually means: 227,917,808 shares, $65,950,296,923, 22.04% of the portfolio.

Accession 0001193125-26-352200 ↗ · reported total $299.25B

Clients

Agents

Keys, pagination and errors: Quickstart

Berkshire Hathaway · Q2 2026 · period 2026-06-30
curl "https://api.ko.io/api/v1/holdings/1067983?ticker=AAPL" \
  -H "Authorization: Bearer $KO_API_KEY"
 
# 200 OK
{ "data": [{
    "ticker": "AAPL",
    "name_of_issuer": "APPLE INC",
    "quarter_date": "2026-06-30",
    "shares_held": "227917808",
    "holding_value": "65950296923",
    "portfolio_weight_pct": 22.04,
    "action": "UNCHANGED"
}] }
Output · 1 row, from 12 filing rows200 OK

Quickstart

Get a free key and make your first call, in curl, Python or TypeScript.

Dataset catalog

Fields, keys, update cadence and source for each of the 23 datasets.

API reference REST

All 44 endpoints with parameters, pagination and example responses.

MCP tools Agents

Connect Claude, Cursor, Codex or any MCP client with one URL.

Direct from the primary sources

Every dataset is collected from the public body that publishes it, with no resold feeds in between. Six of the seven are in and around Washington, DC.

SEC EDGAR

Washington, DC

13F · Form 4 · 8-K · FTD · + more

HOUSE CLERK

Washington, DC

Periodic transaction reports

U.S. SENATE

Washington, DC

Periodic transaction reports

FINRA

Washington, DC · Rockville, MD

Reg SHO threshold lists

FEDERAL RESERVE

Washington, DC

Policy rates

U.S. TREASURY

Washington, DC

Par yield curve

FRED

St. Louis Fed · St. Louis, MO

FRED economic series

Start with the free tier

The free tier includes 200 API calls a day.

Get API keyRead the docs