I'm not an investment banker, but I've analyzed several auto lease securitization deals after the fact within large BB banks.
I just looked at a deal with 7% overcollateralization on 36 month auto leases, four tranches, three rated. The total pool of leases consisted of $239million in collateral, funding $222 million in ABS issued by a bankruptcy remote trust.
"A" rated tranches were priced to yield 7.875 percent