The consumer price index rose by 2.1 percent rise in January, faster than Wall Street analysts expected. The core index, which excludes food and energy, also came in above forecasts, prompting Michael Feroli, an economist at JPMorgan, to describe it as “hotter than Hades.”

While the stock market shrugged off the jump in inflation, bond markets got a bit of a jolt. The yield on the bellwether 10-year Treasury note rose above 2.9 percent on Wednesday, well above the 2.4 percent at which it finished last year.

The scary take on higher yields: To some, the bond market is a particularly prescient predictor of economic trends. So is it picking up on an inflationary surge that the Federal Reserve likely will take too long to recognize? If there’s a scenario guaranteed to scare investors, it’s one in which the Fed, caught out by inflation, has to frantically jack up interest rates.

But the overheating fears may be overdone. The January inflation report was hardly conclusive. Mr. Feroli of JPMorgan, waving away sulfurous fumes for a second, said that the January increase “probably overstates the underlying trend.”

Indeed, the index overshot expectations because two items — clothing and medical services — had very strong increases, according to Pantheon Macroeconomics. Clothing was due for a big rebound because it seemed to lag a lot in recent months, Pantheon asserted. As for medical services, the jump there came from hospital costs, which Pantheon described as “very erratic.”