Banks still are vulnerable to bank runs because they still have deposits so the system is still vulnerable and therefore the Federal Reserve has a set of reserve requirements.

银行仍然对银行挤兑敏感,因为它们仍然有存款,所以这个系统还是比较脆弱的，因此,联邦储备金有一系列的法定准备金率。

耶鲁公开课 - 金融市场课程节选