After the Federal Reserve decided to hold interest rates steady, US borrowing costs have surged to their highest level since 2007. This has sparked concerns that the central bank is struggling to contain the inflationary pressures triggered by President Trump's military actions against Iran. Following the Fed's rate decision on Wednesday to keep its benchmark rate unchanged, the yield on the 30-year US Treasury bond climbed 14 basis points to 5.23%.

This movement reflects growing investor anxiety that the conflict in the Middle East, which is driving up oil prices, could ignite a sustained period of inflation. The yield increase was the largest single-day jump since April 2025, when President Trump's "Liberation Day" announcement sent shockwaves through the market. The Federal Open Market Committee (FOMC) held its key interest rate steady in the 3.5%–3.75% range for the fifth consecutive meeting.

Fed Chair Kevin Warsh stated that the central bank's efforts to curb price increases in the US economy would never "waver." He also noted that the rise in bond yields between the June and July FOMC meetings has effectively tightened monetary policy. "During the interval between these two meetings, financial market pricing has not been idle," Warsh said at the post-meeting press conference. "The market has responded to inflation data on one hand and reflected robust economic growth on the other, pushing both nominal and real interest rates higher."

Prior to the meeting, market expectations for a rate hike on Wednesday were around one-third. This relatively high probability had led some investors to bet on a surprise rate increase. The Fed's decision to hold rates steady, combined with Warsh's emphasis on the market's self-adjustment between meetings, unsettled some traders in the world's largest bond market. "Warsh's answers on inflation today essentially boiled down to 'we are letting the market do the tightening for us,'" said Lou Brien, an economic strategist at DRW Trading. "For the market, that explanation is hard to swallow."

Robert Sorkin, chief US economist at PGIM Fixed Income, noted that "the biggest shortcoming of this press conference was that Warsh didn't explain why they chose not to raise rates." He warned that the sharp rise in long-term Treasury yields is a major red flag, adding, "The Fed will be concerned about the credibility of its own policy, and we will likely see more hawkish signals in the coming weeks." The surge in borrowing costs dragged US stocks significantly lower, with the broad-based S&P 500 falling 1.5%. The Nasdaq 100 Index, which is heavily weighted with technology stocks sensitive to rising bond yields, closed down 2.1%.

Wednesday's rate decision was met with dissenting votes from three FOMC members: Dallas Fed President Lorie Logan, Cleveland Fed President Beth Hammack, and Minneapolis Fed President Neel Kashkari. All three argued for an immediate rate increase. This dissent comes as many investors bet that surging oil prices will trigger a new wave of broad-based inflation, forcing the Fed to raise rates soon. "The FOMC's move was a hawkish hold," said Barclays economist Marc Giannoni. He pointed out that a significant number of committee members favored an immediate rate hike rather than waiting for more economic data, reflecting a strong internal hawkish opposition.

However, during the post-meeting press conference, Warsh insisted, "This Fed's resolve to fight inflation will not waver. Our credibility is built on fulfilling our duties and delivering on our policy commitments." Since the Fed's last meeting in June, the situation with Iran has escalated, nearly halting shipping through the Strait of Hormuz and causing a sharp spike in gasoline and diesel prices. After a fresh attack on a US military base by Iran, President Trump issued a stern warning on Wednesday that he would deliver a heavy blow to Iran.

While central bank officials prefer to look at less volatile measures of underlying inflation, some economists worry that rising energy costs will ripple through the entire supply chain, pushing up costs for both businesses and consumers. The conflict has also amplified the effects of President Trump's tariff policies and the boom in artificial intelligence, further intensifying price pressures in the world's largest economy. The US inflation rate stood at 4.1% in May, well above the Fed's 2% target, a goal the central bank has failed to meet for over five years. Warsh maintained that the central bank would take all necessary measures to bring inflation back to its target level.

Simon Bowmaker, an economics professor at New York University, stated that with growing disagreement among policymakers on whether and when to raise rates, Warsh will face a "severe challenge" in the months ahead. "Every Fed chair faces a test during their tenure. In my view, Warsh's test is coming very soon."