One of the quieter findings in the GAO’s March 2026 federal debt management report (GAO-26-107529) is the degree to which the U.S. government has increased its reliance on short-term borrowing — and what that implies for fiscal exposure to interest rate movements.

In fiscal year 2014, Treasury bills accounted for 13 percent of marketable debt held by the public. By fiscal year 2025 that share had risen to 22 percent, against a long-term historical average of 20 percent. Notes declined as a share but still constitute over half of all outstanding debt. Bonds increased from 12 to 17 percent, partly due to the reintroduction of the 20-year bond in 2020.

The U.S. Government Accountability Office released its March 2026 assessment of federal debt management — GAO-26-107529 — and the headline is technically reassuring: Treasury is meeting borrowing needs. The subtext is not.

Public debt exceeded $31 trillion as of February 2026. In fiscal year 2025 alone, Treasury held 444 auctions to borrow $1.9 trillion for government operations and refinance $9.1 trillion of maturing securities. The Congressional Budget Office projects deficits averaging over $2 trillion annually through 2036. Treasury’s borrowing needs as a share of GDP were 21 percent in 2014. By 2025 they had reached 36 percent.