Average interest rates on U.S. Treasury securities, monthly

Name: Average interest rates on U.S. Treasury securities, monthly
Creator: U.S. Department of the Treasury — Fiscal Data
License: https://fiscaldata.treasury.gov/about-us/
Keywords: interest-rates, treasury, debt, us, yields

Monthly effective interest rates on U.S. Treasury securities outstanding, by marketable vs. non-marketable type and instrument (bills, notes, bonds, TIPS, savings securities and others), in percent per annum at month-end. History from 2001-01.

Source: U.S. Department of the Treasury — Fiscal Data5,009 rowsUpdated: 9/22/2026

interest-ratestreasurydebtusyields

Quality

100

Attribution

U.S. Department of the Treasury, Bureau of the Fiscal Service, Fiscal Data

Schema

Column	Type	Description
date	timestamp	Month of observation, mapped to the first day of the month from the provider's Record Date ("The date that data was published"). Debt to the Penny is published daily; MTS, average interest rates and interest expense are published monthly at month-end.
series_id	string	Stable machine identifier for the series. Built from the provider's own description fields (never the classification_id, which the MTS dictionary notes changes with every publication): debt measures use short slugs of the provider's Display Names; MTS uses monthly_/fytd_/fy_ prefixes; interest-rate and interest-expense series slug the provider's type/group descriptions.
series_label	string	Human-readable series name using the provider's own wording (Display Names and description fields from the Fiscal Data data dictionaries), e.g. "Debt Held by the Public" or "Marketable — Treasury Bills".
unit	string	Unit of value: "USD" for dollar amounts (the provider's CURRENCY data type) or "%" for rates (the provider's PERCENTAGE data type, percent per annum).
value	float	Observed value as a number. Fiscal Data returns missing observations as the string "null"; these become null here. For the MTS deficit/surplus series a positive value means a deficit (outlays exceeded receipts).

Sample rows

date	series_id	series_label	unit	value
2001-01-01T00:00:00	interest_bearing_debt_total_interest_bearing_debt	Interest-bearing Debt — Total Interest-bearing Debt	%	6.594
2001-02-01T00:00:00	interest_bearing_debt_total_interest_bearing_debt	Interest-bearing Debt — Total Interest-bearing Debt	%	6.512
2001-03-01T00:00:00	interest_bearing_debt_total_interest_bearing_debt	Interest-bearing Debt — Total Interest-bearing Debt	%	6.47
2001-04-01T00:00:00	interest_bearing_debt_total_interest_bearing_debt	Interest-bearing Debt — Total Interest-bearing Debt	%	6.426
2001-05-01T00:00:00	interest_bearing_debt_total_interest_bearing_debt	Interest-bearing Debt — Total Interest-bearing Debt	%	6.344

Download sample data

Download the full sample snapshot for this dataset (sample rows, not the complete dataset).

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Use with an LLM

Point any LLM at the metadata endpoint — the documentation above is machine-readable too (JSON-LD + Croissant).

cURL

curl "https://datazimuts.com/v1/datasets/treasury/treasury_average_interest_rates" | jq '{title, rows, columns_count, license}'

Python

import requests

ds = requests.get("https://datazimuts.com/v1/datasets/treasury/treasury_average_interest_rates").json()
print(ds["title"], ds["rows"], "rows")

# Sample rows for an LLM context window
for row in ds.get("sample_rows", [])[:5]:
    print(row)

API endpoint: https://datazimuts.com/v1/datasets/treasury/treasury_average_interest_rates

Tip: fetch /llms.txt for the full machine-readable catalog.