Lisa Cook - the Federal Reserve governor who finds herself at the centre of Donald Trump's ire - was appointed to the role in 2022 by Democratic President Joe Biden, becoming the first African American to serve in the role. There are seven governors on the Fed's board and they each play a key role in setting the monetary policy of the US.

The Fed left its benchmark interest rate unchanged following its July policy meeting amid uncertainty over the impact of tariffs on inflation and economic conditions.

As part of his assault on the Fed, Trump wants to fire policymaker Lisa Cook. Markets are already telling Trump it's a bad idea.