Anyhows, something "unprecedented" is without precedent, that is, is new or unknown, and a "disruption" is something that forces a change of/break with the norm. Thus, the "unprecedented disruption" in this case is market volatility stemming from lower-than-usual liquidity, that might affect earnings.
Australian mortgage lender, Rams Home Loans Group, said, ``unprecedented disruptions'' in credit markets may reduce its profit, leading Australian financial stocks lower.
"Unprecedented" means (as mentioned above) it has never occurred prior to this event. "Unprecedented" is often used as an exaggeration, and may mean that it has not happened in recent memory. But the correct meaning is that it has never happened prior to this event.
A "disruption" is anything that interferes with the normal flow of events. So a traffic accident would be a "disruption" to the effort of getting to work on time.
A phone call while preparing dinner might be a "disruption" to getting to eat dinner at a pre-established time.
So as a whole, the "unprecedented disruptions" means:
Australian mortgage lender, Rams Home Loans Group, said, "Events that had never happened before (or at least in recent memory) caused interference with the normal flow of business" in credit markets and may reduce its profit, leading Australian financial stocks lower.