Investment banks are very different in that a pure investment bank does not accept deposits and it doesn't make loans; it's an underwriter for securities.

投资银行是完全不同的,单纯的投资银行既不吸收存款,也不发放贷款,投行是证券承销商

耶鲁公开课 - 金融市场课程节选

Lots and lots of loans, the securities that people bought at par that were worth about somewhere between zero and $.15 or $.20 and now trade there.

市场上充斥着越来越多的贷款，人们按照面值购买的债券,真正的价值只有大概,0到0。15或者0。20美元0,而它们就这样进行交易。

耶鲁公开课 - 金融市场课程节选

In other words, securities that were themselves backed by subprime loans.

所谓次级债券,就是那些靠次级贷款担保的证券

耶鲁公开课 - 金融市场课程节选