Hedge funds, insurers, and other companies that do business with Wall Street megabanks will pay a price for regulators’ efforts to ensure any future collapse of a giant lender doesn’t tank the entire financial system.

Janet Yellen has been sworn in to succeed Ben Bernanke, becoming the first woman to lead the US Federal Reserve in its 100-year history.

A US plan to force foreign banks to hold far more capital could sow discord among supervisors and lead to retaliation from abroad, EU financial services czar Michel Barnier said last night.