US government borrowing costs surged to a three-year high on Wednesday, September 9, 2026, after the Treasury Department's announcement of a $6 billion bond buyback operation disappointed investors. The Treasury had aimed to suppress high bond yields by buying back 10- to 20-year Treasury bonds, tripling the size of its last long-dated operation. However, the market reacted negatively, with yields rising further instead of easing.
The benchmark 10-year Treasury yield reached 4.85%, its highest level since late 2023. The 20-year bond yield climbed to 5.314%, and the 30-year bond also rose by 5 basis points, surpassing the 5.3% mark to yield 5.307%. This significant increase in borrowing costs is seen as a setback for Treasury Secretary Scott Bessent and the administration, who have been attempting to combat the recent rise in US borrowing costs.
Analysts had varied reactions. Wrightson ICAP analysts noted that tripling the buyback size to $6 billion was a significant escalation, aligning with the spirit of the "at least double" language. However, Mizuho economist Alex Pelle commented that the announced buybacks were less than hoped for, suggesting that the Treasury might need to increase the size further given the market's reaction. Critics, including Stanley Druckenmiller, questioned the impact of the amount on the massive market and warned against governments defending prices, stating, "Governments defending prices against fundamentals always lose." Ryan Sweet, chief economist at Oxford Economics, echoed this sentiment, stating that the bond market is too large for such interventions to significantly alter borrowing costs.
The rise in yields is attributed to several factors, including concerns over the US national debt, which recently exceeded $40 trillion, and investor jitters over energy-driven inflation linked to the Iran war, leading to expectations of interest rate hikes. Brent crude oil surpassed $100 a barrel on the day. Additionally, the Federal Reserve's July meeting minutes, which indicated a potential need for higher rates if inflation doesn't subside, also contributed to the market's unease. The rising yields are expected to further impact the already struggling US housing market by increasing mortgage rates.
Despite the initial negative reaction, yields did retreat slightly from their highs later in the day after a $39 billion sale of 10-year notes saw very strong demand. However, the overall sentiment remained that the $6 billion buyback was insufficient to significantly influence the vast US bond market.
