The threat was made at a press conference with Israeli Prime Minister Benjamin Netanyahu at Trump's Mar-a-Lago residence.
Trump based his accusation on the Federal Reserve headquarters renovation project, which he claimed would cost “more than $4 billion.”
This is not the first time Trump has threatened legal action against Powell, having made similar remarks in August.
Trump also criticized Joe Biden for reappointing Powell and reiterated his desire to dismiss the Fed chair, stating he expects to name a replacement next month.