Entry and exit:
Barriers to entry are high. The most important barriers are economies of scale, patents, access to expensive and complex technology, and strategic actions by incumbent firms designed to discourage or destroy nascent firms. Additional sources of barriers to entry often result from government regulation favoring existing firms making it difficult for new firms to enter the market.
Example: Singtel, a government supported company, already makes it hard for competitors such as Starhub and M1, and needless to say, other small firms do not stand a chance in entering the telecommunications market.