As the Iran war rages on, U.S. Treasury yields – the market's gauge of borrowing costs – have surged to multi-month highs, pricing in delayed Fed rate cuts and higher inflation expectations.

The question is at what point the Treasury market, which underpins global finance, starts causing trouble for both the government and the economy, forcing the Trump administration to rethink the war or consider a mechanism to cap yields.

According to ING, that point comes when a little-known 10-year U.S. Treasury swap spread blows past 60 basis points. We are not there yet.

"Watch the 10-year swap spread. It's just below 50bp now. If that were to shoot to 60bp, it would spell enough trouble to ultimately shape the war path. Why? It's a measure of the de-rating of Treasuries. We need to steer clear of that. It's not just the negative perception, it's the added cost of funding U.S. debt," Padhraic Garvey, CFA and regional head of research Americas at ING, said in a note to clients Friday.

Garvey emphasized that rising swap spreads aren't just about perception; they increase the implied cost of funding for the U.S. government, making it more expensive for the heavily-indebted Uncle Sam to issue new bonds and borrow more. This could ripple through the financial system, tightening credit conditions and leading to risk aversion in both stocks and bitcoin BTC$70,509.66.

"Narrow swap spreads are the good look. Wide swap spreads are the opposite," he said.

Focus on the 10-year yield

Other observers are focused on the 10-year Treasury yield, the benchmark rate that sets borrowing costs across the U.S. economy, influencing risk-taking in both the economy and financial markets.

Since the Iran war began at the end of February, the yield has surged roughly 45 basis points to 4.37%.

According to The Kobeissi Letter, the 4.5%–4.6% range represents a critical “line in the sand.” That’s the level at which President Trump pulled back from his sweeping Liberation Day tariffs last April.

“This is in line with the rapid surge seen around ‘Liberation Day’ in April 2025. As the 10-year note yield surged above 4.50%, President Trump began floating a potential tariff pause. And, once the yield broke above 4.60%, he officially implemented a 90-day pause on reciprocal tariffs on April 9th, 2025,” the letter noted on X.

Put simply, the bond market could soon reach a point where the Trump administration feels pressured to temper the war.

On Tuesday, President Donald Trump paused attacks on Iranian infrastructure, claiming productive talks with Iran, though Iran denied having any contact. Meanwhile, early Wednesday, U.S. and Israeli forces reportedly struck new Iranian energy facilities, including a natural gas pipeline in Khorramshahr.

If the yield breaks the 4.5%–4.6% range, it could rise to 5%, the level analysts have flagged as a make-or-break point for risk assets in recent years.

According to The Kobeissi Letter, the U.S. economy cannot sustain a 5% level in the 10-year yield.

Arthur Hayes, co-founder of BitMEX and chief investment officer at Maelstrom Fund, has previously stated that a potential rise in the 10-year yield above 5% could trigger a mini-financial crisis, forcing the Fed to step in with liquidity injections.

In other words, bitcoin could initially drop in a knee-jerk reaction, but liquidity injections could quickly recharge bulls.

The takeaway is clear. bitcoin traders need to closely track Treasury yields and swap spreads, as shifts in these markets could directly influence risk appetite and policy decisions.