Loeb's hedge fund, Third Point, had owned about 7% of Sony, whose entertainment arm, Sony Entertainment Inc., includes film and television studio Sony Pictures Entertainment, Sony/ATV Music Publishing and Sony Music Entertainment.
Loeb later ratcheted up his rhetoric in public pleas for the company to adopt his proposal and said in his second-quarter 2013 letter to Third Point investors that Sony's entertainment arm "remains poorly managed." He also criticized Hirai for giving "free passes" to Sony Pictures Chairman and CEO Michael Lynton and co-Chairman Amy Pascal.
"We still managed to generate nearly a 20% return on this investment before exiting," the letter said.
Sony rejected Loeb's spinoff plan in August 2013, but the studio committed to big changes a few months later. At a November 2013 investors conference, Sony Pictures said it would cut costs and concentrate more on television.
The studio has achieved cost reductions by eliminating jobs, and there have been several rounds of layoffs at the company in the last year.
Sony Pictures also has reshuffled its executive ranks, saying goodbye to Marc Weinstock, formerly its head of domestic and international marketing, and Chris Cookson, formerly president of Sony Pictures Technologies, among others.
Sony Pictures has also added several high-profile executives to the fold.
Also, in September, the new film company of Jeff Robinov, the former Warner Bros. Pictures Group president, signed a distribution deal with Sony Pictures. Sony will distribute up to six movies a year from the new firm, called Studio 8.
This year, Loeb has largely remained quiet when it comes to Sony. In January, the Los Angeles Times reported that, according to a source with knowledge of Loeb's thinking at the time, the recent changes at the studio -- from the budget cuts to a new emphasis on television production -- had left the hedge fund investor "hopeful."
For the fiscal first quarter that ended June 30, Sony Pictures posted operating income of $78 million, up 109% from a year earlier. Revenue increased 23% to $1.93 billion.
Sony Pictures declined to comment, saying: "We don't comment on any specific investor's shareholding."