Complex sentence: In 1991, after privatisation, Canal 13 went to Arte Radiotelevisivo Argentino S.A. (Artear), whose major shareholder is the company that publishes the daily newspaper "Clarín".
Split into simpler sentences: In 1991, after privatisation, Canal 13 went to Arte Radiotelevisivo Argentino S.A., a company popularly known as "Artear". Its major shareholder is the company that publishes the daily newspaper "Clarín".