They define four credit risk categories and they define a formula involving the amount of assets in each of the categories.

他们定义了四个风险等级,然后根据每个风险等级下的资产额,定义了一个资产总额的计算公式

耶鲁公开课 - 金融市场课程节选

Well, we don't have much oil relative to the size of our portfolio.

考虑到资产总额的话,我们其实持有的石油其实不多。

耶鲁公开课 - 金融市场课程节选