Monopoly May exist in some industry due to the nature of the business and the technology involved .
these include such services as electric and water supply, oil and gas distribution, air and rail transportation,etc.
In many countries these industries are either controlled by the government or are entrusted to one large firms because of organizations logistics.
Monopolies may also exist in situations wherein one firm signs an exclusive contract, preventing others from entering a specific market.
For example, the railways may give the contract for running buffet car on trains to a single company, thus giving it monopoly in this area