The frantic efforts to shore up Credit Suisse come as assurances from policymakers - from the European Central Bank to U.S. President Joe Biden - that the global banking system is safe fail to assuage fears about broader troubles in the sector. Already this week, big U.S. banks had to swoop in with a $30 billion lifeline for smaller lender First Republic, while U.S. banks altogether sought a record $153 billion in emergency liquidity from the Federal Reserve in recent days.