Getty ImagesThe US central bank has cut its key interest rate again as Donald Trump’s election as president raises new uncertainty about the future for borrowing costs.The cut puts the Federal Reserve’s lending rate in the range of 4.5%-4.75%. It marks the second drop in a row after the Fed lowered rates for the first time in more than four years in September, indicating confidence that price rises were finally stabilising.Forecasters have been expecting borrowing costs to fall further in the months ahead but warned that Trump’s plans for tax cuts, immigration and tariffs could keep pressure on inflation and drive up government borrowing, complicating those bets.Interest rates on US debt have already jumped this week, reflecting those concerns.The decision comes the same day that the Bank of England warned that it could take longer for borrowing costs to fall, warning that inflation could creep higher after last week’s Budget.“On both sides of the pond, we are seeing expectations for future rate cuts being scaled back considerably compared to what many had originally hoped for,” said Lindsay James, investment strategist at Quilter Investors.”In the US it seems interest rates will stay higher for longer as the Fed will need to tread very carefully until it is better able to assess the true impact of Trump’s plans.”The Fed’s key rate – what it charges banks for short-term borrowing – sets a benchmark for lending across the economy, influencing how banks set interest rates for credit cards, mortgages and other loans.Those borrowing costs have been hovering at the highest rates in two decades, after the Fed rapidly hiked rates in response to inflation in 2022, bringing its key rate to roughly 5.3%. The cut announced on Thursday, which was widely expected and unanimous, lowered rates by 0.25 percentage points. The Fed had started cutting rates in September as confidence increased that the pace of price rises in the US was getting under control and job gains were starting to slow. Inflation in the US stood at 2.4% in September, down from more than 9% in June 2022, according to the latest official figures.Concerns had flared earlier this year about rising unemployment, but those quietened in September, after data showed an unexpectedly strong burst of hiring.However, the latest figures showed almost non-existent job growth in October, when the country was grappling with hurricanes and strike actions.Federal Reserve chairman Jerome Powell said on Thursday officials were equally focused on keeping prices stable and the job market healthy, echoing language used in their last meeting.He said at a press conference after the rates announcement that with appropriate shifts in the Fed’s policy, “strength in our economy and the labour market can be maintained, with inflation moving sustainably down to 2%”.