Government filings say Mitt Romney may have worked at Bain Capital longer than he's publicly suggested.

Romney has repeatedly said he left Bain in 1999 to lead the 2002 Winter Olympics in Salt Lake City. But according to the Boston Globe, Bain's filings with the Securities and Exchange Commission say Romney remained the firm's "sole stockholder, chairman of the board, chief executive officer and president" until 2002.

The Globe also reports that Romney's financial disclosure forms filed in Massachusetts list him as the sole owner of Bain Capital in 2002 and say he earned money as a Bain "executive" in 2001 and 2002.

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The timing is notable because Romney has said his resignation from the company in 1999 meant he was not responsible for companies owned by Bain that went bankrupt or laid off workers after that date. But both Bain Capital and the Romney campaign disputed the story, the latter describing the article as "inaccurate."

"As Bain Capital has said, as Gov. Romney has said, and as has been confirmed by independent fact checkers multiple times, Gov. Romney left Bain Capital in February of 1999 to run the Olympics and had no input on investments or management of companies after that point," Romney spokeswoman Andrea Saul said in a statement.

Bain Capital issued a similar statement, insisting Romney has had "absolutely no involvement with the management or investment activities of the firm or with any of its portfolio companies since the day of his departure" in February 1999.

"Due to the sudden nature of Mr. Romney's departure, he remained the sole stockholder for a time while formal ownership was being documented and transferred to the group of partners who took over management of the firm in 1999," the company said in a statement. "Accordingly, Mr. Romney was reported in various capacities on SEC filings during this period."

[Related: WSJ editorial slams Romney campaign]

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But the Obama campaign immediately seized on the report, slamming Romney's "big Bain lie." It used the article to press on with its calls for Romney to release more information about his personal finances, questioning whether the GOP nominee is "concealing his tax returns" because he's trying to hide something.

"It's time for Mitt Romney to come clean so that the American people can make their own judgments about his record and his motivations," Stephanie Cutter, Obama's deputy campaign manager, said in an email to reporters.

In a subsequent conference call with reporters, Cutter suggested that Romney had either lied to the public or to the SEC—which, she noted, is a "felony." That prompted an angry response from Romney campaign manager Matt Rhoades, who called Cutter's charge "so over the top that it calls into question the integrity of their entire campaign."

"President Obama ought to apologize for the out-of-control behavior of his staff, which demeans the office he holds," Rhoades said in a statement. "Campaigns are supposed to be hard fought, but statements like those made by Stephanie Cutter belittle the process and the candidate on whose behalf she works."

The Washington Post's Fact Checker, which had previously looked into the question of when Romney left Bain, said in a piece published Thursday morning that it stood behind its earlier finding that Romney was not technically running the company, even if his name was on legal documents.

"Just because you are listed as an owner of shares does not mean you have a managerial role," Glenn Kessler, who authors the Post's Fact Checker section, wrote.