THE BURNED OVER DISTRICT

When they seek to break up foreign companies for their own benefit.

An American hedge fund billionaire known for starting big fights has called for a breakup of the entertainment and electronics colossus Sony, according to people briefed on the matter, possibly setting off a battle that could roil Japan’s famously staid corporate culture.

The call, which came on Tuesday, will most likely be viewed by government officials and corporate leaders in Tokyo as a shot across the bow from Wall Street, just as Western investors begin piling into Japanese stocks.

The hedge fund manager, Daniel S. Loeb, is pressing Sony to spin off part of its entertainment arm, which includes one of the biggest film studios in Hollywood and one of the largest music labels in the world, responsible for movies like “Skyfall” and artists like Taylor Swift.

Mr. Loeb — known for ousting Yahoo’s former chief executive and luring Marissa Mayer away from Google to run the company — also signaled that he would accept a seat on Sony’s board.

His hedge fund has quietly amassed a stake of about 6.5 percent in Sony, making it one of the biggest shareholders. The holding, made up of stock and derivatives, is valued at about $1.1 billion.

Still, even big Japanese investors have often faced resistance in seeking changes at companies, a hurdle that may be significantly higher for a foreign hedge fund manager.

A spokesman for Sony, Shiro Kambe, said in a statement that the company welcomes investments. “We are focused on creating shareholder value by executing on our plan to revitalize and grow the electronics business, while further strengthening the stable business foundations of the entertainment and financial services businesses,” he said.

But Mr. Kambe also pointed to repeated assertions by Sony’s chief executive, Kazuo Hirai, that Sony Entertainment contributes significantly to the overall company and is not for sale. “We look forward to continuing constructive dialogue with our shareholders as we pursue our strategy,” he said.

And the very polite "Fuck you" from the company spokesman.