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.