Fed's Interest-Rate Tool Loses Grip as Bond Market Decouples
In brief
- Federal funds rate doesn't directly move mortgage rates or government debt service costs despite Fed control.
- 10-year Treasury yield now responds to deficit projections and bond issuance, not Fed policy alone.
- Federal debt reached $37.6 trillion in September 2025, with $1.2 trillion annual interest and $2+ trillion yearly deficits.
The Decoupling
For the better part of the last 50 years, bond market forces ran in roughly the same direction as Fed policy. Inflation expectations stayed contained. Investors trusted the central bank's inflation narrative. When the Fed raised rates, long-term yields rose. When it cut, they fell.
That symmetry is gone.
The Fed trimmed 100 basis points across three cuts at the end of 2024. The 10-year yield barely moved. By September 2025, after a further cut, the 10-year was nearly unchanged from where it had been a year earlier. Rate cuts are failing to pull down long-term yields. The bond market had effectively decoupled from the Fed.
Why the Lever Broke
Federal debt reached $37.6 trillion as of September 2025, with annual interest payments hitting $1.2 trillion in fiscal year 2025 alone. The Congressional Budget Office projects deficits above $2 trillion annually for the next decade.
After the pandemic, the U.S. government borrowed at a scale with no modern parallel. Treasury issued $30.2 trillion in marketable securities across fiscal year 2025 to refinance maturing debt and fund new borrowing. The $30.2 trillion represents 36% of GDP.
Bond investors have responded accordingly, pricing US debt with an eye on deficit trajectories and issuance pipelines rather than waiting for Fed decisions. They're no longer betting on inflation containment—they're pricing in fiscal reality.
The Modern Inversion
RBC Wealth Management analysts described the current situation as a modern inversion of Alan Greenspan's famous conundrum. In the mid-2000s, Greenspan found that rate hikes failed to lift long-term yields. Powell has found that rate cuts since 2024 are failing to pull them down.
The symptom of this breakdown is visible in Fed emergency operations. It has also resumed expanding parts of its balance sheet again to support market liquidity. If emergency support is still needed during relatively calm periods, the traditional transmission mechanism—the path from Fed policy to real-world borrowing costs—has fractured. The Fed can cut rates. It can expand its balance sheet. But it can't force bond markets to follow when investors see trillion-dollar deficits ahead.
