s/
Stockslash
⌘K
For developers

MCP API for value-investor data.

Programmatic access to super-investor portfolios, SEC 13F filings and institutional ownership data, purpose-built for AI agents. One endpoint, 16 tools, JSON-RPC 2.0.

POSThttps://stockslash.com/api/mcp
16tools
JSON-RPC 2.0
v2024-11-05
Ask things like
"What stocks did Warren Buffett buy this quarter?"
"Which funds own the most Apple shares?"
"Show me the latest SEC filings from top investors."
01

Connect

Free and open — no API key required. POST JSON-RPC 2.0 requests to the endpoint below. Rate-limited to 200 requests per 15 minutes per IP.

bash
POST https://stockslash.com/api/mcp
Content-Type: application/json
02

Add to Claude

Pick your MCP client. No key or signup needed — paste and go.

Claude Code (CLI)

bash
claude mcp add --transport http stockslash \
  https://stockslash.com/api/mcp
After running, restart Claude Code and the stockslash tools will appear. Verify with /mcp.

Claude Desktop

Edit your config file:

macOS~/Library/Application Support/Claude/claude_desktop_config.json
Windows%APPDATA%/Claude/claude_desktop_config.json
json
{
  "mcpServers": {
    "stockslash": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://stockslash.com/api/mcp"
      ]
    }
  }
}
Save and restart Claude Desktop. The server will appear in the MCP menu.

Cursor

Add to .cursor/mcp.json (per-project) or ~/.cursor/mcp.json (global):

json
{
  "mcpServers": {
    "stockslash": {
      "url": "https://stockslash.com/api/mcp"
    }
  }
}
03

Quick start

List every available tool — the simplest sanity check that the endpoint is reachable:

bash
curl -X POST https://stockslash.com/api/mcp \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Call a tool — for example, fetch the top-valued funds:

python
import requests

r = requests.post(
  "https://stockslash.com/api/mcp",
  json={
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "get_super_investors",
      "arguments": {"type": "portfolio-value"}
    }
  },
)
print(r.json())
04

Tools (16)

Institutional vs insider: get_stock_holders returns funds (BlackRock, Vanguard); get_insider_trades returns executives and directors (Form 4).
Investors
Tool
Purpose
Required
Optional
get_super_investors
List all tracked funds with portfolio snapshot (CIK, value, top holdings)
—
type, sort, limit
get_investor_current_holdings
All stocks owned by one fund for a quarter
cik
quarter
get_investor_fund_value
Total portfolio value for one fund (latest)
cik
—
get_investor_fund_value_history
Quarterly portfolio value history for one fund — AUM over time
cik
—
get_fund_activity
Buys and sells made by one fund in a quarter
cik
quarter
get_fund_distribution
Buy/sell distribution for one fund across quarters — trading cadence
cik
—
Stocks
Tool
Purpose
Required
Optional
get_stock_holders
Institutional funds holding a given stock (13F filers)
stockSymbol
quarter
get_stock_activity
Trading activity for a stock across all funds
stockSymbol
quarter
get_ownership_statistics
Institutional ownership percentages for one stock
stockSymbol
—
get_insider_trades
Form 4 insider trades (executives, directors) for a stock
stockSymbol
limit, transactionType
get_sp_stocks_by_holders
S&P 500 stocks ranked by number of institutional holders
—
limit
Market
Tool
Purpose
Required
Optional
get_latest_filings_updates
Most recent 13F-HR filings across all tracked funds
—
limit
get_filings_buy_status
Stocks being bought/added in recent filings
—
quarter, limit
get_filings_sell_status
Stocks being sold/exited in recent filings
—
quarter, limit
get_ownership_statistics_home
Homepage summary: top owned, most bought, most sold
—
—
get_latest_quarter
Latest quarter with available 13F data
—
—
All quarter filters use the form Q4-2025. Omit to get the latest quarter.
05

Common workflow — resolve a name to a CIK

Investor-specific tools take a cik, not a name. To go from "Warren Buffett" to holdings:

  1. Call get_super_investors and find the matching row.
  2. Read its cik field.
  3. Pass the CIK to get_investor_current_holdings, get_fund_activity, get_fund_distribution, etc.

Known CIKs (handy for testing)

0001067983Berkshire HathawayWarren Buffett
0001037389Pershing SquareBill Ackman
0001649339Scion Asset ManagementMichael Burry
0001056831Fairholme CapitalBruce Berkowitz
0001167483Tiger GlobalChase Coleman
06

Errors & limits

429Rate limit (200 req / 15 min per IP)
-32601Unknown method (typo in method field)
-32602Invalid params (missing required arg, wrong type)
-32000Tool execution error (upstream data issue)
Protocol version 2024-11-05. New tools may be added without breaking existing ones — handle tools/list dynamically rather than hard-coding the set.