It’s not a phrasal verb, but a verb with a prepositional object. “To snooze” is to sleep, nap, or fall asleep. It often implies a short period of sleep. “Over” is just a preposition, referring to the previously mentioned noun. The investors snoozed over either the ’60 pages of “risk factors”’. In other words, they found those pages boring and did not read the with their full attention.