investment is only meaningful if there is a way to dispose it and convert to cash when the need arises. with a house co-owned by 2 or more different parties, and 1 of them staying inside it, how can the investors dispose it to realize their profit?

one way is to have a new market in which the so called investment can be freely traded. that is just an derivative similar to subprime like many said, no? and what decides the trading price of such investment?