The proportionate share of the value of the intangible property of such companies as do business in this and other states, growing out of the use of their tangible property in this state under their franchises, privileges, and contracts, shall have its situs in this state and in the several counties and municipalities thereof in which they exercise their rights; provided, that property of any such owner located outside of the state which is not directly used in the business to which the property in the state is devoted shall not enter into the value of the property within the state to be assessed.