Oil fell almost 4% and the economic data were weak, so why did the US 30-year Treasury yield climb to its highest in more than 20 years? Wasn't it a day when everything pointed to lower rates?

The reason yields are rising has changed

The usual drivers of long-term yields are inflation and the Fed. On 9/29, both pointed toward lower yields. Oil fell, consumer sentiment and job openings were weak, and the probability of an October hike dropped to 51%. In fact, the 2-year yield, which is most sensitive to Fed expectations, fell to 4.88%. Yet the 30-year alone rose. That gap is the answer.

A long-term bond yield breaks down into two main pieces. One is the expected path of the policy rate; the other is the extra compensation investors demand for tying up money for a long time, known as the term premium. 9/29 was a day when the first piece fell and the second rose by more. This pattern, with short-term yields falling and long-term yields rising, is called bear steepening.

Why the term premium is widening now

1. Supply pressure

When long-term yields move independently of oil or data, it is usually a question of "who is going to buy all these Treasuries." The weak 5-year auction on 9/23 was already a warning light, and with the new fiscal year starting 10/1, issuance plans are back in focus. Jamie Dimon's remarks align with this reading.

"The crowding out is coming from the government. Borrowing large sums of money, which is inflationary." — Jamie Dimon, JPMorgan CEO (Bloomberg Tech, 2026-09-29)

2. Doubt that inflation will be contained even if the Fed pauses

President Williams' "no need to rush" was good news for short-term investors, but long-term investors may read it as a signal that "the Fed could step back with inflation in the high 3% range." The less hawkish the Fed, the more compensation investors demand for long-term inflation risk. That is why fading hike expectations and rising long-term yields came on the same day.

3. Weaker overseas demand

A report that French public debt has hit a record 119% of GDP coincided with Japan's BOJ hiking to 1.25% and Australia hiking to 4.60%. When government bond yields rise everywhere, foreign investors have less reason to buy long-dated US Treasuries.

Is it the same as October 2023?

The closest precedent is October 2023. The 30-year also topped 5% then, and models attributed much of the rise not to policy rate expectations but to the term premium (MUFG Americas, 2023-10). The causes were similar too: the Treasury was sharply increasing long-dated supply while the Fed was shrinking its balance sheet (MUFG Americas, 2023-10).

What turned the tide then was not economic data but the Treasury's quarterly refunding announcement. On November 1, 2023, the Treasury increased long-dated issuance by less than expected (US Treasury press release, 2023-11-01), long-term yields reversed, and the 10-year fell sharply through year-end.

There are differences. In 2023 oil prices were stable, but today Hormuz transit is still only 77% of pre-war levels, leaving a risk of an oil spike. With supply factors and inflation factors both alive at once, the current situation is trickier.

What investors should watch

• Don't rush to buy the dip in long-term bond ETFs (TLT). If rates are rising because of supply and credibility rather than the Fed, long-term bonds may not rebound even when slowdown data come out. 9/29 is an example
• The next turning signal is the Treasury's quarterly refunding announcement in early November. If it restrains long-dated increases as in 2023, the term premium could come out. Until then, collecting yield in short-term bonds (SGOV, etc.) while waiting offers better reward for the risk
• Watch the gap between the 2-year and 30-year. If it keeps widening, loan and mortgage rates won't come down even if the Fed pauses. In that case, assets that depend on long-term financing, such as long-duration growth stocks, REITs and small caps, come under pressure first
• Conversely, if the 10/2 jobs report is very weak, the 2-year plunges and the 30-year follows it down, that will be the first sign that the driver of higher yields has shifted back to the economy