The studio is making fewer films these days, and enjoying smaller market share.
However, Pitt didn't make many movies for Paramount, and the Viacom Inc.-owned company has insisted it is comfortable with a new, leaner approach to the business.
"Paramount's paradigm is a different model," said Richard Walter, a professor at UCLA's School of Theater, Film and Television. "It's a business organization run by MBAs, and I am not saying that in a pejorative way."
Plan B, which was formed in 2002 by Pitt and then-wife Jennifer Aniston, has released only three movies with Paramount since signing a first-look deal with the studio in 2005.
The most recent film, this summer's zombie thriller "World War Z," grossed $540 million worldwide. But the expensive Marc Forster-directed movie, which starred Pitt, suffered from production issues and required reshoots.
The two other Plan B movies put out by the studio weren't big moneymakers. Pitt's company produced the comedy "Year of the Dog" and the thriller "A Mighty Heart" for Paramount's specialty film division Paramount Vantage. Both movies came out in 2007, with "Year of the Dog" taking in $1.6 million worldwide and "A Mighty Heart" topping out at $18.9 million.
Plan B's deal with Paramount expires Dec. 31. On Tuesday, a pair of production companies aligned with Paramount rival 20th Century Fox announced a new multiyear deal with Pitt and his company. One of them is New Regency, which co-financed and co-produced arguably Plan B's most celebrated success — "12 Years a Slave." Paramount had no involvement in the critical darling, which was distributed by Fox Searchlight Pictures and on Wednesday was nominated for four SAG Awards — the most for any film.
The picture, about a free man who is kidnapped in 1841 and sold into slavery, is a commercial success but not a blockbuster. It has grossed $35 million worldwide since being released by Fox Searchlight in October, according to Box Office Mojo.
"We had a great experience with Plan B on '12 Years a Slave' and next year's 'True Story' and we really like each other," New Regency Chief Executive Brad Weston said. "It was a really organic outgrowth of a great relationship."
A Paramount spokeswoman said studio executives were unavailable for comment. Plan B didn't return phone calls seeking comment.
During Plan B's Paramount tenure, the production company found major success at other studios. Among the box-office or commercial successes Plan B produced elsewhere were "Kick-Ass," released in 2010 by Lions Gate Entertainment Corp. and grossed $96 million worldwide; and the 2011 prestige picture "The Tree of Life," which was directed by Terrence Malick, released by Fox Searchlight and took in $54 million worldwide.
Paramount could continue to benefit from its association with Pitt and Plan B. The studio is moving forward with Pitt on a "World War Z" sequel, which "The Impossible" director Juan Antonio Bayona would direct. That project could be far more lucrative than the sort of art-house fare for which Plan B has mostly shown an appetite.
Losing Pitt could mean losing cachet and buzz. But that loss could be offset by the news last week that the studio had signed a deal with Jerry Bruckheimer, one of Hollywood's most powerful producers. "The Transformers" and "Pirates of the Caribbean" filmmaker, who in the 1980s was based on the Paramount lot and had a string of hits there, signed a three-year, first look deal with the studio last week. He will make "Top Gun 2" and a " Beverly Hills Cop" film for the studio, which released the originals in those series to great success in the 1980s.
"The Bruckheimer deal probably at least compensates for if not exceeds the Pitt deal in terms of potential long-term positive financial impact," entertainment business analyst Hal Vogel said in an interview.
Paramount has put out fewer movies than its rivals in recent years and seen its market share shrink as a result. This year, Paramount will release 10 movies, and plans to put out 12 next year.
Warner Bros., the biggest movie studio in terms of films released annually, will put out 18 films this year and 17 next year. According to Box Office Mojo, Paramount was No. 7 in terms of box-office market share this year as of Dec. 1. Last year it also finished seventh but was No. 1 in 2011.
However, Paramount is profitable. For the fiscal quarter that ended Sept. 30, the studio posted adjusted operating income of $291 million, up 49% from a year earlier. Revenue was up 11% to $1.2 billion.
"If you look at the economics, market share clearly is a barometer that people look at, but the barometer that Viacom looks at — and our shareholders look at — is our margins," Paramount Chairman and Chief Executive Brad Grey told The Times last week. "We have a business plan that works for us creatively, as well as for our shareholders."
Times staff writer John Horn contributed to this report.