Total US public debt outstanding stood at $40.52 trillion on Oct. 30, an increase of $352.7 billion from Sept. 30, the Department of the Treasury said.
The increase amounted to 0.9% over the month. Debt was $2.42 trillion higher than on Oct. 30, 2025, an increase of 6.3% over about a year.
Debt held by the public accounted for $32.74 trillion of the total, while intragovernmental holdings, debt held within the federal government, amounted to $7.79 trillion, the department said.
The public debt total includes both categories. The amount held by the public was the larger component, while intragovernmental holdings accounted for the rest of the outstanding balance.
Accrued interest expense, interest recorded as it builds up, totaled $63.1 billion in September and $800 billion for fiscal 2026, according to the department.
The latest interest figures cover the month recorded on Sept. 30. They precede the Oct. 30 debt balance by a month, so the debt and interest totals reflect different periods.
Treasury notes accounted for the largest interest expense in both periods. Interest on those securities totaled $43.5 billion in September and $498.3 billion for the fiscal year.
Treasury bonds ranked second, with interest expense of $15.3 billion for September and $178.2 billion for fiscal 2026. Both amounts were below the corresponding expenses on Treasury notes.
Together, notes and bonds accounted for most of the interest expense in September and for the fiscal year. The other listed categories each carried smaller expenses in both periods.
Inflation compensation on Treasury Inflation-Protected Securities, known as TIPS, was the third-largest listed interest category for the fiscal year, at $69.7 billion. September's amount was negative $452 million.
That category therefore reduced the September interest total, even though its expense for the full fiscal year was positive. It was the only listed category with a negative monthly amount.
Treasury floating rate notes carried interest expense of $2.3 billion in September and $26.7 billion for fiscal 2026. They ranked ahead of the separate inflation-protected securities category in both periods.
The separate TIPS securities category accounted for $2.1 billion in September interest expense and $24.4 billion for the fiscal year. Those amounts were distinct from the inflation compensation category.
State and local government certificates of indebtedness, notes and bonds accounted for $218.9 million in September interest expense. Their fiscal-year expense totaled $2.7 billion, the smallest annual amount among the categories listed.