An open economy is a type of economy where not only domestic factors but also entities in other countries engage in trade of products (goods and services). Trade can take the form of managerial exchange, technology transfers, and all kinds of goods and services. (However, certain exceptions exist that cannot be exchanged; the railway services of a country, for example, cannot be traded with another country to avail the service.) It contrasts with a closed economy in which international trade and finance cannot take place.