Since federal debt held by the public crossed 

three official daily 10-year Treasury observations above 5%

And today, the 10-year has traded as high as 

That historical combination is the signal.

America has experienced 5% Treasury yields before.

America has experienced federal debt above 90% of GDP before.

And the difference between touching 5% and staying above it matters.

As old low-rate Treasury debt matures, it gets refinanced at prevailing rates. The longer yields remain this high, the more of the federal debt stock gets repriced into substantially higher interest costs.

High debt + 5% long-term rates + persistent deficits = a fiscal combination with almost no modern track record.

We aren't looking back at decades of data to understand how this works.

We're watching the experiment happen now.

econ

Since federal debt held by the public crossed **90% of GDP**, America has experienced only **three official daily 10-year Treasury observations above 5%**.

All three happened in the **past eight days**:

**September 16 — 5.01%**  
**September 18 — 5.01%**  
**September 23 — 5.11%**

And today, the 10-year has traded as high as **~5.14%**, which would make this the **fourth trading day above 5%** in the high-debt era.

That historical combination is the signal.

America has experienced 5% Treasury yields before.

America has experienced federal debt above 90% of GDP before.

What it has barely experienced is **both at the same time**.

And the difference between touching 5% and staying above it matters.

As old low-rate Treasury debt matures, it gets refinanced at prevailing rates. The longer yields remain this high, the more of the federal debt stock gets repriced into substantially higher interest costs.

**High debt + 5% long-term rates + persistent deficits = a fiscal combination with almost no modern track record.**

We aren't looking back at decades of data to understand how this works.

We're watching the experiment happen now.