Sage Adviasory's Komson Silapachai and Thomas Urano laid out a case this week that deserves close attention from anyone managing duration in a fixed income portfolio. Writing in their September 15, 2026 "Notes from the Desk" brief — A Rate Hike into a Flatter Curve1 — the pair argue that while the Fed is almost certainly about to tighten again, the more consequential story is playing out not at the short end of the curve, but at the long end, and the implications run deeper than a simple yield-level conversation.
The Setup: Hike Is Coming, But That Is Not the Point
Silapachai and Urano open with the obvious: the data has been clear. "This month's economic readings reinforced expectations that the Fed will deliver another rate hike at this week's FOMC meeting and pushed the expected policy path higher." Markets are not hedging their bets. "Markets are now pricing nearly four rate hikes through 2027, among the highest tightening expectations seen in years." That is the starting position. But the Sage strategists quickly move past the headline to focus on what is actually driving the steepness, or rather the coming flatness, of the yield curve.
Long Yields: Driven by Supply, Not Just Inflation
The reason long-term yields have already been rising is structural and, importantly, distinct from the near-term policy narrative. Silapachai and Urano note that "concerns around persistent deficits, rising debt-service costs, and heavy Treasury issuance have driven long-term yields higher as investors demand greater compensation to own government debt." This is a term premium story as much as it is an inflation story. Investors are being asked to absorb more government paper at a time when fiscal credibility is under scrutiny, and they are extracting a price for doing so.
Yet the counterintuitive thesis Sage puts forward is that once the Fed begins hiking in earnest, the long end may actually find relative support. The mechanism is historical and well-documented. "Previous hiking cycles have frequently coincided with a flatter yield curve as short-term yields tend to rise alongside policy expectations, while longer-term yields often move less as markets begin looking beyond the next rate hike toward the eventual impact on growth and inflation." In short: short rates follow the Fed, but long rates follow the future. And the future the long end is pricing is not one of perpetual tightening.
The Wildcard That Could Rewrite the Script
If there is a variable that Silapachai and Urano are watching most carefully, it is energy. "The key wildcard remains energy, both in markets and politics, as well as the broader inflation path." Fuel prices have not cooperated with the disinflation narrative. "Fuel prices have resumed their ascent in recent months, with diesel reaching new highs." The risk from here is transmission: "There is a risk that higher transportation and logistics costs could filter through supply chains, placing upward pressure on inflation." This is the channel that could keep the Fed's hand forced longer than markets expect.
But Sage does not stop at the upside risk. The authors introduce a countervailing force that the market may be underweighting: base effects. "If the inflation pressures this year stay isolated to one-time shocks, such as energy, the role of base effects could come into play next year." And the math could be striking. "Even if monthly inflation prints remain elevated, higher base effects could produce noticeably lower year-over-year CPI readings six months from now, helping to ease some concerns around the long-term inflation outlook."
The Bigger Picture: The Policy Clock Moves Faster Than Consensus
The piece closes with a reminder that markets routinely anchor to present conditions and underestimate how quickly the policy calculus can shift. "Policy expectations can shift far more quickly than the market anticipates." The hike this week may happen, but the Sage view is that today's pricing reflects today's fears, not necessarily tomorrow's reality. "This week's meeting may bring rates another step higher, but the outlook one year from now will depend less on where inflation is today and more on whether today's pressures prove persistent." And if energy-driven inflation proves transitory: "the Fed could find itself discussing a much different set of risks by this time next year than the ones currently reflected in market pricing."
Five Key Takeaways for Advisors and Investors
1. A Fed rate hike this week is almost certain, but the hike itself is less important than what the yield curve does in response — history suggests it flattens, favoring the long end relatively.
2. Long-term yields have been driven higher by supply and fiscal concerns, not just inflation expectations, meaning the term premium dynamic deserves independent attention.
3. Energy is the dominant wildcard. Diesel at new highs and its potential supply-chain transmission are the most credible upside threats to the inflation trajectory.
4. Base effects are being underpriced. Even with elevated monthly prints, year-over-year CPI readings could fall sharply in six months, creating a very different backdrop for policy discussion.
5. Advisors should resist anchoring fixed income positioning to current market pricing. Silapachai and Urano's core message is that the policy outlook twelve months from now may look nothing like the four-hike scenario markets are pricing today.
Footnote:
1 Silapachai, Komson, and Thomas Urano. "A Rate Hike into a Flatter Curve." Sage Advisory, 15 Sept. 2026, https://www.sageadvisory.com/article/a-rate-hike-into-a-flatter-curve.
