Senate Democrats have launched an investigation into JPMorgan Chase's banking relationship with convicted sex offender Jeffrey Epstein, escalating scrutiny of major financial institutions' historical ties to him. Democratic staffers on the Senate Finance Committee plan to examine decisions involving Epstein made by Mary Erdoes, CEO of JPMorgan's Asset & Wealth Management business, a source told CNBC. The probe follows broader investigations Democrats were preparing after victories in Tuesday's midterm elections, with the committee likely to be chaired by Sen. Ron Wyden, D-Ore., in the next Congress. JPMorgan shares fell 3% during the trading session as investors weighed potential regulatory and reputational risks for the largest U.S. bank by assets.