Previous studies of news market suggested that media companies typically slant news content. One purpose of slanting is to suit readers’ preference. We measure news slant in Korean news market and try to show the determinant of slant. We select 9 newspapers and 3 broadcasting companies and choose 10 news items during the period of 2008 to 2010. News slanting of a media company is measured in each news item by counting the number of political citations quoting from different political parties.Comparing values from news slant measure, we find news companies highly separated on a linear political spectrum of liberal and conservative. Major newspapers are located at either far-right or far-left, while broadcasting companies are located at the middle. Minor newspapers are found to strategically hold the middle position. Media companies offer product differentiation through news slanting. The degree of product differentiation is almost 10-times higher for newspapers news than broadcasting news. In Korea, we have more fierce competition in newspapers market and relatively lower level of competition in broadcasting news market. Higher level of product differentiation in Korean newspaper explains this phenomenon.Our major finding is that media companies continuously change the citations mix from liberal and conservative parties in news coverage. Media companies are inclined to increase citation from a political party who is gaining political support from people. As people change their support level toward different political parties, media companies adjust the citation mix in their news coverage to match the demand change. Major newspaper companies are clearly found to change their news citation source to match changes in political landscape. For small newspaper companies and broadcasting news companies, however, the adjustment to changes in demand is not detected. We find that political issues with narrow deviations in people opinion are covered very similarly by almost every news companies. These three findings altogether suggest that news slanting in Korean news market is quite demand-oriented.