The long-term Treasury yield is the most important price in the world. – Stanley Druckenmiller
The long-term Treasury yield is the most important price in the world.
Federal net interest expense reached 18.5% of revenue in 2025, surpassing the previous record of 18.4% set in 1991. However, the circumstances around that burden look very different from those in 1991. The U.S. 30-year Treasury yield was around 8% then and had spent much of the prior decade in double digits. Today, it is only a little above 5%. The federal government has reached a record interest burden with the long bond nowhere near a record yield.
The difference is the size of the federal debt held by the public today. Federal debt held by the public in 1991 was equivalent in size to 44% of gross domestic product, and it is now roughly equal in size to the entire U.S. economy. A much larger stock of debt has left the government with a similar interest burden at much lower borrowing costs. Comparing today’s 5% long bond with the much higher yields of prior decades overlooks the dramatic change in the fiscal backdrop. The yield itself might look ordinary by historical standards, but the government’s sensitivity to it is not.
That heightened sensitivity makes the long end of the Treasury curve more important. The 30-year yield influences borrowing costs far beyond Washington and is a market-clearing price for long-duration capital. It is also being set at a time when demand for capital is unusually intense. In Blog 136, AI Capex Is Still Booming as Momentum Slows, we note that hyperscaler capital spending is expected to reach about $760 billion this year and will increasingly depend on outside financing as buildout outstrips internally generated cash. The U.S. Treasury Department is therefore raising enormous sums at a time when private-sector financing needs are also unusually large.
On Aug. 19, the Treasury announced that it would double the size of its long-dated bond buybacks from $2 billion to at least $4 billion per operation in the 10- to 30-year sector. Treasury officials describe the expanded operations as liquidity support. The line between liquidity management and price management has begun to blur. This helps explain why the government is paying more attention to the long end.
A 5% 30-year bond yield might appear ordinary compared with earlier decades. What is not ordinary is the fiscal burden attached to it. Net interest expense has already reached a record share of revenue, while the Treasury continues to finance large deficits in a market with heavy private demand for capital. That makes the level of the long bond more consequential than the historical comparison alone suggests.
Between the Lines is a weekly blog by DoubleLine Portfolio Managers Sam Garza, Joseph Mezyk and Quant Analysts Fei He, CFA and Sunyu Wang that breaks down topical macro and market issues. For questions or suggestions please e-mail us at betweenthelines@doubleline.com. The views and opinions expressed herein are those of the authors and do not necessarily reflect the views of DoubleLine Capital LP, its affiliates or employees.
