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US Treasury Average Interest Rates by Security Type

Monthly average interest rates on US Treasury marketable securities (bills, notes, bonds, TIPS, FRNs) Latest months first. Data only, not advice.

x402: $0.003 per callMCP tool: us_treasury_rates

Input

ParameterTypeDefaultDescription
monthsinteger3Number of most recent months.

* required

Source and freshness

Source and licence
U.S. Department of the Treasury, Fiscal Data (public domain). Average interest rates are month-end averages on outstanding securities, not market yields.
Last verified
2026-10-03 (hourly check against the live source)

Use it

HTTP (x402)

curl -i "https://api.ambolt.dev/v1/us-treasury-rates?months=2"

Returns 402 Payment Required with the price until an x402 payment is attached; @x402/fetch does this for you. See Get started.

MCP

{ "mcpServers": { "ambolt": { "url": "https://api.ambolt.dev/mcp" } } }
# then call the tool: us_treasury_rates

Apify

Not published as an Actor yet.

Example response

{
  "months": [
    {
      "recordDate": "2026-08-31",
      "rates": [
        {
          "security": "Treasury Bills",
          "ratePct": 3.788
        },
        {
          "security": "Treasury Notes",
          "ratePct": 3.345
        },
        {
          "security": "Treasury Bonds",
          "ratePct": 3.453
        }
      ]
    },
    {
      "recordDate": "2026-07-31",
      "rates": [
        {
          "security": "Treasury Bills",
          "ratePct": 3.758
        },
        {
          "security": "Treasury Notes",
          "ratePct": 3.309
        },
        {
          "security": "Treasury Bonds",
          "ratePct": 3.442
        }
      ]
    }
  ],
  "source": "Source: U.S. Department of the Treasury, Fiscal Data (public domain). Average interest rates are month-end averages on outstanding securities, not market yields.",
  "fetchedAt": "2026-10-02T21:36:03.043Z"
}

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