Why do some houses don't sell right away?

[Shannon X.]

I'm sure this is an easy question for many, however I wanted too see what the answers would be. Currently on MLS their are about 20 house that were listed from the beginning of the month as REO. Now, does this mean that no investors are putting in offers cause they want too much, or do investors see it as not a good city, house to invest in and the numbers don't work?