• May U.S. CPI expected to rise to 4.2% year-over-year, up from 3.8% in April, driven by higher energy costs from the Iran conflict.
  • Core CPI is anticipated to edge higher to around 2.9%, signaling persistent inflation beyond energy.
  • Markets are increasingly pricing in a possible Fed rate hike later this year, with a hotter-than-expected reading likely to trigger a stronger market reaction.

Inflation Watch: May CPI Report Looms

The U.S. consumer price index for May is due out today, and economists expect headline inflation to accelerate to 4.2% year-over-year, according to a Bloomberg survey. That would mark a notable pickup from April's 3.8% reading, driven largely by surging energy prices as the Iran conflict continues to disrupt global oil supplies (XOM).

"Energy shocks from geopolitical tensions are pushing headline inflation higher, complicating policy calibration for the Federal Reserve," said a senior economist at a major investment bank, who asked not to be named discussing private forecasts. Core CPI, which excludes food and energy, is forecast to rise to 2.9% from 2.8%, indicating that price pressures are broadening beyond the volatile energy component.

Investors are bracing for volatility. According to people familiar with market positioning, options markets are pricing in a potential 10-basis-point swing in 10-year Treasury yields following the release. A hotter-than-expected print could reinforce expectations that the Fed will need to raise rates later this year, a scenario that has already been creeping into fed funds futures.

"If inflation prints hotter than expectations, markets could favor a hawkish shift in policy expectations, potentially strengthening the USD and pressuring rate-sensitive assets," said a fixed-income strategist at a European asset manager. The CME FedWatch tool now shows a 30% probability of a rate hike by December, up from 20% a month ago.

The Biden administration has been reluctant to intervene in energy markets, but officials are monitoring the situation closely. The Iran conflict has added a $10-15 premium to crude prices, according to industry analysts, and the impact is flowing through to gasoline and heating oil.

Some economists warn that the inflation surge could be more persistent than the Fed expects. "Historical patterns show energy-price-driven inflation can spill into broader goods and services inflation, prompting central banks to tighten policy to keep inflation anchored," said a research note from a Washington-based think tank. The 2022 energy squeeze saw core inflation remain elevated for months after oil prices (CVX) peaked.

Correction: An earlier version of this article incorrectly stated the April CPI reading as 3.9%. It is 3.8%.