Suppose you are a naive investor and you say, okay I'm going to invest in companies' paper, which is their promise to pay --their IOU.

假如你是一个菜鸟投资者,想投资于这些公司的债券,债券就是他们的偿还凭证或者说欠条

耶鲁公开课 - 金融市场课程节选

I may have an "IOU" From someone or I may own a bond from someone that promises to pay me something in a year or two years.

也许我握有一份欠条,或是一份合约,某人承诺,在一年或者两年内支付我一些钱

耶鲁公开课 - 金融市场课程节选

What you could do hundreds of years ago-- and can still do it today-- was go to a bank and present this bond or IOU and say, "What will you give me for it?"

在数百年前你们能做的,在今天还是能够做到的就是,到银行出示这份合约或欠条,问,你们根据它能给我多少钱

耶鲁公开课 - 金融市场课程节选