Inflation, the rate of price increases, has come down significantly in the US since 2022, when it shot past 9%.
Investors had been expecting the Federal Reserve, which had hiked rates to the highest levels in more than two decades to fight the problem, to cut rates this year as a result.
But further progress has been limited in recent months. Combined with a string of strong economic data, it has raised doubts about that plan.
Investors are also nervous that plans by President-elect Donald Trump for tariffs, mass migrant deportations and tax cuts could put upward pressure on prices.
The Fed is widely expected to keep its key rate, which now stands at about 4.3%, unchanged at its meeting this month.
