Property rights are essential to a free-market principle because it gives the owners of their property full control over its use. This full control enables property owners to use their resources in the most efficient way possible, and maximize the total benefit of these resources.
When property rights are not guaranteed, the free-market system suffers significantly. When people to not have fulls rights to their earned property, and also have the ability to claim/steal the property of others, an efficient free market system is impossible.
