Methodology Treasury Fiscal Data 'Average Interest Rates on U.S. Treasury Securities', 'Total Marketable' roll-up row. Monthly weighted average across bills, notes, bonds, TIPS, and FRNs, via the Bureau of the Fiscal Service.
Related series Provenance
Source U.S. Treasury Fiscal Data Publisher U.S. Department of the Treasury, Bureau of the Fiscal Service Series ID avg_interest_rate_amt License US public domain Latest value observed 2026-07-31, vintage 2026-08-06 Fetched from https://api.fiscaldata.treasury.gov/services/api/fiscal_service/v2/accounting/od/avg_interest_rates?fields=record_date,avg_interest_rate_amt&filter=security_type_desc%3Aeq%3AMarketable%2Csecurity_desc%3Aeq%3ATotal%20Marketable&sort=record_date&page[size]=10000&page[number]=1 Transform none — values as published Revisions never overwrite history: each upstream change lands as a new vintage, and prior vintages stay queryable. See methodology .