Treasury Yields Climb as Iran War Inflation Shock Drives Bear-Flattening Flow

The immediate economic shock is a direct supply disruption. The closure of the Strait of Hormuz by Iranian forces has triggered a 65% surge in Brent crude since the conflict began. This spike in global energy prices is the primary driver of the Treasury yield move, as traders price in a renewed inflation threat.

The market's reaction is clear in the 10-year yield. It has climbed nearly 20 basis points since the war started, reversing earlier declines. The yield hit a recent peak of 4.468% on March 27, its highest level since July 2025. This move reflects a bear-flattening flow, where longer-dated yields rise faster than shorter ones.

The mechanism is straightforward. The war's inflationary pressure has caused traders to scale back expectations for Fed rate cuts. Even as the Fed is still seen cutting rates this year, the fear is that inflation is "more stubborn than people expect," making the case for a dovish pivot weaker.

The Bear-Flattening Flow Signal

The market's repricing is happening fastest at the front end. The 2-year Treasury yield has jumped nearly 60 basis points to 3.96%, while the 10-year yield has climbed more slowly to 4.46%. This aggressive bear-flattening pattern-where shorter-dated yields rise faster-is the key signal.

The mechanism is clear. Front-end yields are more sensitive to near-term Fed policy expectations. The surge reflects a sharp repricing for more hawkish monetary policy, as traders now anticipate the Fed may keep rates higher for longer to combat stubborn inflation. This is a classic move, as noted by BCA Research's strategist: "the aggressive bear flattening of yield curves reflects a hawkish monetary policy repricing in response to inflation fears stemming from the Iran war."

The parallel in Europe is stark. German 2-year yields jumped to 2.65%, and 10-year yields climbed to around 3%. This global pattern underscores that the repricing is not isolated but a coordinated reaction to the war's inflationary shock, with front-end yields leading the charge.

Catalysts and Flow Risks

The immediate catalyst is a 10-day US pause on strikes through April 6, aimed at allowing negotiations. Yet, this window is a double-edged sword. Some investors fear it could be used to build up additional forces, prolonging the conflict. The risk is that a failure to de-escalate will extend the inflation shock, keeping oil prices elevated and Treasury yields under pressure.

Key flow signals to watch are oil prices and Treasury auction results. Oil is trading near its 2022 highs, and a poor auction last week already pressured yields higher. Any further deterioration in these metrics would confirm the bearish inflation trade and likely sustain the yield climb.

The bottom line is persistent volatility. Bonds have lost their safe-haven status this month, falling alongside stocks. With gold also down sharply, investors have fewer places to hide. This broad-based selloff means volatility persists, and the market's repricing for higher-for-longer rates is far from complete.