Activist investor Dan Loeb has disclosed a $1.5 billion stake in Sony Corp. and pushed the company to make dramatic changes, including spinning off its semiconductor business and listing it in Japan.

Sony¡¯s shares rose 3.1 percent in Tokyo after Loeb¡¯s Third Point published a letter and 102-page presentation pushing for changes at the Japanese media and electronics giant, including potential sales of its stakes in a financial affiliate and companies such as Spotify Technology SA.

If Sony spins off the semiconductor business and executes on its long-term vision, the new entity could be worth $35 billion within five years, according to the New York-based hedge fund firm. A representative for Sony declined to comment. Friday¡¯s move gives it a gain of about 3 percent for the year, roughly in line with the Japanese market.