G'day

I am an American who has been living in Australia for the last 15 years.  I am thinking about trying to buy  a bank owned or foreclosed home in the USA as an investment. I rang our bank to ask them if they had any other clients that invested in overseas properties but they told me NO, that THEY DON'T HOLD SECURITIES ON ANY PROPERTIES OVERSEAS. 

Now I am wondering why won't Australian banks hold securities on properties overseas?

Does anybody out there know the reason for this?

 I am just curious that's all.