A former Fannie Mae manager said he was subjected to threats and intimidation after complaining about accounting problems at the mortgage-finance giant, according to written testimony he gave to Congress.

Roger Barnes, who worked in Fannie Mae’s controller department, said he was forced from his job after complaining to top officials that company accounting for the cost of mortgages might be improper. Mr. Barnes gave his account to a House committee holding hearings on a regulator’s findings that Fannie misapplied accounting rules in order to report stable earnings.

Fannie Mae is “plagued by a corporate culture that uses threats, intimidation, and reprisal” Mr. Barnes told the House Financial Services Committee. Employees who want to report improprieties “cannot risk doing so, fearing the retaliation that they know will follow,” Mr. Barnes said in a 25-page statement.

Mr. Barnes said he first complained in 1999 about how Fannie Mae amortized costs or benefits of mortgages and mortgage securities in its portfolio. He said he repeatedly raised concerns, including in a September 2002 memo to the chief executive officer, Franklin Raines, and the chief financial officer, Timothy Howard.

“The atmosphere and culture, particularly within the Controller’s Division, is one of intimidation, restraint of dissenting opinions, and pressure to be part of the ‘Team,”‘ he said. That team gave Messrs. Raines and Howard desired results “to please the markets,” according to Mr. Barnes’s statement.

Fannie Mae’s regulator, the Office of Federal Housing Enterprise Oversight, issued a report last month that said the company used “cookie jar” reserves and deferred expenses to smooth earnings and meet executive bonus targets.

The report identified weaknesses in internal controls and a corporate culture that emphasized stable earnings. Ofheo blamed Mr. Howard for many of the accounting errors, which the regulator said have “potentially large” financial consequences.

Messrs. Raines and Howard, and Ofheo’s director, Armando Falcon Jr., testified at the committee hearing about the report’s findings. Messrs. Raines and Howard, who did not admit any wrongdoing in response to the Ofheo report, did not refer to Mr. Barnes’s statement in their testimony.

Mr. Raines said he and the company “strongly disagree” with Ofheo allegations that Fannie Mae violated accounting rules to maximize executive bonuses. He said he looks forward to having the dispute, which concerns accounting for mortgage amortization and changes in derivatives values,to be settled by the U.S. Securities and Exchange Commission.

Mr. Howard testified that the applicable rule on derivatives “is widely considered to be the most complicated accounting standard ever issued.” He said he and other company officials “did not intend” to engage in the “sham transactions” alleged in the Ofheo report.

“We took this issue very seriously,” said Fannie Mae spokeswoman Janice Daue of Mr. Barnes’s complaints.

Mr. Barnes said Fannie Mae managers ostracized him for complaining that “it appeared” the company used an amortization modeling system to manipulate reported income, “which would constitute fraudulent conduct” in violation of federal law.

After complaining for years, Mr. Barnes said, he was stripped of duties, excluded from meetings, downgraded in job reviews, and denied promotions before leaving in October 2003.

Barnes said many employees “knew or suspected that the company was regularly engaging in improper income management, and it became a joke that the controller’s division could produce any income statement that the company wanted.”