Social ownership refers to the various forms of ownership for the means of production in socialist economic systems; encompassing public ownership, employee ownership, citizen ownership of equity and common ownership. Historically social ownership implied that capital and factor markets would cease to exist under the assumption that market exchanges within the production process would be made redundant if capital goods were owned by a single entity or network of entities representing society, but the articulation of models of market socialism where factor markets are utilized for allocating capital goods between socially owned enterprises broadened the definition to include autonomous entities within a market economy. Social ownership of the means of production is the common defining characteristic of all the various forms of socialism.