Total US federal debt outstanding stood at $40.59 trillion on Oct. 29, an amount that included debt held by the public and government accounts, the Treasury Department said.
The total increased by $496.7 billion, or 1.2%, from Sept. 29. It rose by $2.52 trillion, or 6.6%, from Oct. 29, 2025, the department said.
Debt held by the public accounted for $32.71 trillion of the total. Intragovernmental holdings, the debt held within the federal government, accounted for the remaining $7.88 trillion.
The interest figures cover September, while the debt figures show the amount outstanding on Oct. 29. The latest supplied monthly interest expense therefore covers an earlier period than the debt total.
Accrued interest expense, interest recorded as it builds up on outstanding debt, totalled $63.1 billion in September. The total for fiscal 2026 through September reached $800 billion.
Treasury notes accounted for the largest interest expense in both September and the fiscal year to date. Interest on those securities totalled $43.5 billion for the month and $498.3 billion for fiscal 2026 through September.
Treasury bonds were the second-largest category over both periods. They accounted for $15.3 billion in September interest expense and $178.2 billion in the fiscal year to date.
The two categories together accounted for $58.9 billion of September's $63.1 billion total. Their combined fiscal year expense reached $676.5 billion, out of the $800 billion total through September.
Inflation compensation on Treasury Inflation-Protected Securities had the third-largest fiscal year interest expense among the categories supplied, at $69.7 billion. Its September entry was negative $452 million.
The inflation compensation entry was separate from the interest expense category for Treasury Inflation-Protected Securities. That category accounted for $2.1 billion in September and $24.4 billion in fiscal 2026 through September.
Treasury floating rate notes accounted for $2.3 billion in September interest expense. Their fiscal year total reached $26.7 billion, putting them below inflation compensation and above the separate inflation-protected securities category for that period.
The state and local government certificates of indebtedness, notes and bonds category accounted for $218.9 million in September. Its fiscal year interest expense totalled $2.7 billion, the smallest fiscal year amount among the categories supplied.
The September total includes the negative inflation compensation entry alongside the positive expense amounts. For the fiscal year to date, each of the six supplied categories recorded a positive interest expense.