Imagine a corporate client has a $10 million revolving credit line, currently drawn at $2 million. If they default tomorrow, what is our Exposure at Default (EAD)? Why isn't it just the $2 million they currently owe?

假设一个企业客户有1000万美元的循环信用额度（Revolving line），目前只提取了200万。如果他们明天违约，我们的违约风险暴露（EAD）是多少？为什么不是他们目前欠我们的200万？