Foreclosed Properties Not Listed on MLS

[Katharine Gonzalez]

Question: I've been scouring my local county assessor's database and have come across properties whose owners are listed as banks. After researching a little further I have found that a property has been foreclosed on, may even be vacant, but is not active on the MLS. My question is this: Are these properties acquirable? What reasons could there be for not being listed on the MLS?

Thanks in advance!