Margin rate data for AI assistants and developers: MCP server

Add it to your AI assistant

Server URL (Streamable HTTP, no key, read-only):

https://stockmarket.loans/mcp

Claude (claude.ai and the desktop app): Settings, then Connectors, then Add custom connector. Paste the URL and save. No sign-in is needed.
ChatGPT: Settings, then Apps and Connectors. Turn on Developer mode under Advanced, choose Create, paste the URL and set authentication to none.
Grok: grok.com, then Connectors, then New connector, then Custom. Paste the URL.
Perplexity: Settings, then Connectors, then Add custom connector, then MCP. Paste the URL and choose no authentication.
Mistral Le Chat: Intelligence, then Connectors, then Add connector, then Custom MCP connector. Paste the URL.

Claude Code:

claude mcp add --transport http stockmarket-loans https://stockmarket.loans/mcp

Cursor (~/.cursor/mcp.json) and other clients that read mcpServers:

{
  "mcpServers": {
    "stockmarket-loans": {
      "url": "https://stockmarket.loans/mcp"
    }
  }
}

VS Code (.vscode/mcp.json):

{
  "servers": {
    "stockmarket-loans": {
      "type": "http",
      "url": "https://stockmarket.loans/mcp"
    }
  }
}

Gemini CLI (~/.gemini/settings.json):

{
  "mcpServers": {
    "stockmarket-loans": {
      "httpUrl": "https://stockmarket.loans/mcp"
    }
  }
}

Menu names change as the apps update. If a step has moved, look for "connectors" or "MCP" in the app's settings.

Tools

Tool	What it returns	Try asking
`get_margin_rates`	One broker's published margin schedule: every balance tier and rate, the base rate and its date, maintenance notes, the schedule date and the broker's source link.	What margin rate does Schwab charge on $100,000?
`compare_brokers`	Every compared broker's published rate on one balance, lowest first, with the yearly interest and the brokers that print no rate at that size.	Which broker has the lowest margin rate on a $250,000 loan?
`borrowing_cost`	What a balance costs over a number of months at each broker's rate, the same math as the margin interest calculator, beside any rate you were quoted.	What would borrowing $200,000 against my stocks cost over 6 months compared with a 6.5% SBLOC quote?

Discovery file: /.well-known/mcp.json. For bulk use, every tier is a free CSV and JSON download on Margin rate data.

License and attribution

The compilation is CC BY 4.0: credit "Data: Stockmarket Loans (stockmarket.loans)" with a link. The rates are each broker's published figures. Stockmarket Loans is an independent website, not a broker-dealer, lender or investment adviser, and is not affiliated with any broker. Nothing returned is a quote, an offer or investment advice.

Questions

Is there a cost or an API key?

No. The server is free, read-only and needs no key or sign-in. Please cite the stockmarket.loans page or the broker source that comes back with each answer.

Where do the rates come from?

Each broker's own margin rate page or fee schedule, with the date the broker prints, last checked 2026-10-24. Interactive Brokers rates follow its USD benchmark plus the printed spread. The server reads the same file as the pages on this site.

Is a result a quote or a recommendation?

No. It is the broker's published rate and simple-interest arithmetic. Brokers change rates without notice, large accounts often negotiate, and the broker's own disclosure governs.

Questions or a data error: hello@stockmarket.loans. Privacy and terms.

Broker margin rates as an MCP server

Add it to your AI assistant

Tools

License and attribution

Questions