(Yes this is a little older thread…but it’s slow here, and I just signed up for an account.)
One thing to be aware of is that the meaning of “excess” can/does vary depending on context. In my prior life doing pricing/product work for one particular class of business, it was not uncommon to look at an account that had (for example) a $9m excess liability policy atop a set of $1m primary policies that were themselves excess of a $500k SIR.
If the requested limits are high enough, it’s possible to have facultative reinsurance covering a certain amount excess an attachment point in the excess liability coverage layer…just to confuse matters further.
I tend to think of “umbrella policy” and “excess liability policy” as being almost interchangeable, except that “excess liability” in my experience is more likely to be written above some other carrier’s paper than umbrella, and sometimes (but not always) “excess liability” is really just shorthand for “follow-form excess liability”, where many (but not all) terms and conditions are inherited from the primary policies, as opposed to umbrella which is more likely to have its own, discrete conditions.