Liberating "dead IP" from large companies

How much is "dead IP" worth to large companies?

Let's assume that company X has "IP" Y.
Y has not been used in 10 or 20 years,
and X is content to sit on Y forever and let it rot.
What would it take to free Y from X?
(And presumably do something useful with it.)

I guess the goal is to come with a solution that
looks like salt for hides from both perspectives.

-Brendan

Depends on past lucrativity and scope of the IP.
If we be talking something serial and critically acclaimed such as Wing Commander, good chances they'll be looking for several good millions or so.
___________
Black Sky
We'll breach the 2D game engine conventions yet!

Is Wing Commander still live?

How much do you suppose a single platform one off that
sold ~200k copies ten years ago would be worth? MULE?
Something that put a company out of business due to a
lawsuit? (I know that "it depends", regardless.)

-Brendan