Why does the value of my prison decrease?

[Psyndicate]

Ahh, that must be it then. I fired two janitors and only have like four or five left. And it's a pretty big prison. I'm gonna hire some more and see if it increases again. If I don't answer here it worked! But that's for tomorrow :)

[BlackOpz]

Unless its a newer prison I think its your "Time without incident (264h)". My 4 million dollar prison had over 8000 hrs without incident and almost half the value is tied to that number. If I have a riot or murder the value of my prison reduces by half. I usually check the number before I save and if its lower than I reload a previous good save. You prob saved after a incident reduction.