IATSE, which represents not just stagehands but computer-graphics engineers and hair and makeup professionals, declined to comment.
"At this time, IATSE has no comment on the Michael Moore film," said IATSE publicist Katherine Orloff.
An organized labor source confirmed Moore and the union were in talks, even though the movie is completed and slated for release on Friday, Oct. 2.
Moore's admittedly left-leaning and darkly satiric films have long enraged conservatives, who have closely examined the director's expenses and business practices looking for signs of hypocrisy.
Production costs for "Capitalism" have not been made public. "Sicko," his 2007 film about the healthcare industry cost $9 million to produce and earned $24.5 million at the box office. His 2004 film "Fahrenheit 9/11," about the Bush administration's handling of the Sept. 11, 2001 attacks, cost $6 million and earned $119 million.
"Capitalism: A Love Story" argues that deregulation and greedy business executives undermined the economic system, mostly benefitting the country's richest people at the expense of the working class.