Marginal Credit

Will Emerson: These here are the historical volatility limits which, of course, our trading model relies on pretty fucking heavily. Well, we're now so levered up that once it gets outside of these limits, it gets ugly in a hurry.
Sam Rogers: And how close to these limits have we gotten?
Will Emerson: Sam, we're beyond close. We broke through these limits five or six days in the last two weeks.
--Margin Call

Not sure what the corporate universe was for the analysis, but picture reflects the decline in corporate credit quality over the past decade.

Very few AAA companies left--probably even fewer than indicated as credit rating agency scales have relaxed.

Couple that with a burgeoning stable of junk and, once again, the stage is set for credit events.