Some customers want to use your safe because safes are hard and expensive to get and some -and then you've got all this gold, so you might as well lend it out.

顾客需要使用你的保险箱,因为对个人而言保险箱既昂贵又难以获得,这样你就拿到他们的金子,然后你可以把金子借出去

耶鲁公开课 - 金融市场课程节选