The activist hedge fund manager Daniel S. Loeb has raised his bet on Sony as he continues his campaign to persuade the embattled Japanese giant into spinning off part of its entertainment arm.
In a letter to Sony’s board sent on Tuesday morning Tokyo time, Mr. Loeb disclosed that his firm, Third Point, had raised its stake to about 7 percent, or about 70 million shares. That is up from 6.5 percent last month.
The letter is a sign that Mr. Loeb, who is embarking on a rare effort by an outsider to shake up one of Japan’s most respected companies, isn’t going away anytime soon.
Mr. Loeb praised Sony’s responses to his calls for change, noting the company’s hiring of banks to weigh the partial spinoff of the entertainment business, and he suggested that Kazuo Hirai, Sony’s chief executive, should serve as the chairman of both companies.
But giving the entertainment business its own board would, in Mr. Loeb’s estimation, provide better oversight over revival efforts and spending plans.
Since going public with his calls for change at Sony, Mr. Loeb has kept a polite, even deferential tone. But his latest letter is slightly more urgent.
“Shareholders should not have to wait any longer,†Mr. Loeb wrote. “We support efforts to create an integrated Sony ecosystem but must not forget that today the company’s most valuable untapped synergies lie within entertainment itself.â€
A representative for Sony was not immediately available for comment.
