I've got about 10 minutes before my private tour of Sirius XM HQ's.
About that sudden drop yesterday, my opinion on the matter is as follows:
There was a certain SEC filing issued by the company recently that gave notice that certain stockholders would sell from time to time. These types of drops are usually indicative of such transactions as a large number of shares are offered for sale all at once.
I saw a reference that 1 person had been responsible for that drop. More likely than not, this is what occurred.