问题如下：
Five tranches of auto loan asset-backed securities (ABSs) are issued with a face value of $6,000,000 and pay an average coupon of 5.2%. The value of the auto loans is $6,800,000, and they have an average interest rate of 5.4%. The fee for servicing the ABS is 0.2%. Which of the following credit enhancements are involved with this transaction?
选项： Excess spread.
Margin step-up.
C.Subordinating note classes.
D.Overcollateralization.
解释：
D This ABS is supported by overcollateralization because the value of the asset pool is greater than the value of the securities. There is no excess spread involved because there is no difference between the cash inflows from the underlying assets and the cash outflows in the form of interest payments on the ABS issues.
你好，能举一个Margin-Step up和excess spread的例子吗
