All appeals are dismissed.

The costs of appeal by the plaintiff are assessed against the plaintiff and the defendant.

The grounds of appeal are examined.

1. Case summary and key issue

A. According to the reasoning of the lower judgment on the case, the following facts are revealed.

(1) The current market situation C Co., Ltd. (hereinafter referred to as “stock company” in the name of each company), D, and E (hereinafter referred to as “manufacture 3 Co., Ltd.”) are domestic business operators manufacturing mobile phones (hereinafter referred to as “terminal”).

At the time of 2010, the market share of the third manufacturer was about 85% in total.

In the domestic mobile communications service market, I, J, and the plaintiff (hereinafter referred to as "three mobile communications companies") are competing.

(2) Of the devices distributed domestically, approximately KRW 85% of the device distribution structure (A) was supplied from the manufacturer to the mobile carrier’s agent, sales store, etc. (hereinafter collectively referred to as “distribution network”).

(hereinafter “business model”). In the case of a device supplied directly from a manufacturer to a distribution network without going through a mobile carrier, the mobile carrier is able to open the device only by registering the device information.

Accordingly, the distribution structure of the device has been formed as the center of the mobile carrier.

(B) In the essential complementary relationship between a device and a mobile communications service, the consumer generally purchased a device from the distribution network and entered into a mobile communications service contract.

The promotion method for mobile operators to pay subsidies was activated on the condition that mobile operators take the lead of the distribution of mobile devices and participate in mobile communications services.

(3) The price structure of the device (A) generally refers to the price at which the manufacturer sells the device to the mobile operator, and the price at which the mobile operator sells the device to the agency is called “supply price.”

The ex-factory price of a device is known to consumers through the media, etc.

(b) the manufacturer or the mobile carrier shall promote the sale of a device.